Hi Guys,



Here's another question I got wrong in one of the tests...



Q18. Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

1)2 of the interior angles of ABCD are right angles
2)The degree measure of angle ABC is twice that of angle BCD

I'll post the correct answer shortly...

thanks,
shipra

i guess the answer is E....
using st.1, we knw that the sum of other two angles = 180 deg. so possible combinations can be 60,120 or 50,130 etc..
using st.2, we do not knw the exact measure cuz the quadrilateral can have angles as 50,100,200,10 or 60,120,40,140 etc..
using both st. together,
if we consider angle ABC = 90 deg (one of the right angles), then other angle will be 45 deg..so the angles of quad can be 90,90,45,135
or, the other solution set can be 60,120,90,90...so u dont hv a unique answer on tht too...

Hi Guys,



Here's another question I got wrong in one of the tests...



Q18. Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

1)2 of the interior angles of ABCD are right angles
2)The degree measure of angle ABC is twice that of angle BCD

I'll post the correct answer shortly...

thanks,
shipra

q3. Set S consists of n numbers arranged in asc. order. A new set is created as follows: each element in S is increased by a value = that number's place in S. By how much does the mean of the new set > the mean of the original set?
1) set S has 10 elements
2) The sum of elements in the original set is 100.

I think the answer is A.

Reason: The increase in the new set is always a constant. Let that constant be C.

Now, if the sum of terms in the original set is x and the number of terms is n, then the mean is x/n.

Now upon increase the mean would be (x+C)/n.

Hence the increase would be ((x+c)/n) - (x/n) = C/n. To get this number we will need the number of elements n (using which C can be determined, too). Hence Choice 1 suffices.

For choice 2, while it is said that the numbers are arranged in ascending order, we are not given any information about what numbers these are. Hence the sum of the numbers doesnt give us any information to determine n.

Vikram.

q1. A company enlisted P people to sell 200 knives each, and each salesperson then enlisted P more people to sell 200 knives each. If eveyone sold their 200 knives, what is the value of P?
1) the first P people sold 1/9 of all the knives sold?
2) 14,400 knives were sold in total.

The first P people sold 200 knives each. Hence there were totally 200P knives with them. Each of these P then hired another P to sell 200 each. Hence we now have 200 * P * P.

Hence we have 200P^2 + 200P = x.

Now we need a value for x to solve this equation. Choice 2 gives us this information directly. Hence, the choices are down to B or D. Choice 1, while not giving us the total number of knives directly, tells us that

200 P = x/9. Hence x = 1800P. Substituting this value in the above equation will also help us solve it.

Hence the answer is D.

Vikram.

Hi,
Here are a few DS questions I couldn't solve,

q1. A company enlisted P people to sell 200 knives each, and each salesperson then enlisted P more people to sell 200 knives each. If eveyone sold their 200 knives, what is the value of P?
1) the first P people sold 1/9 of all the knives sold?
2) 14,400 knives were sold in total.
q2. A group of theater owners made an arrangement with an acting company stating that the theater owners would get $5 for every ticket sold. How much did the theater owner earn from the ticket sales?
1) The total revenue was $700
2) If 30 more tickets had been sold, the theater owners would have recvd 30% more money from ticket sales.
q3. Set S consists of n numbers arranged in asc. order. A new set is created as follows: each element in S is increased by a value = that number's place in S. By how much does the mean of the new set > the mean of the original set?
1) set S has 10 elements
2) The sum of elements in the original set is 100.
q4. 3 segments are drawn from opposite corners of a hexagon to form 6 triangles. These segments all bisect each other at pt A. Are the triangles equilateral?
1) All 6 sides are the same length.
2) The 3 segments drawn between the opposite corners are the same length.

Can somebody please help me solve them?




Thanks,
Shipra

q.2:
answer is B acc. to me....
st.1:
u cannot answer using this st.
st.2:
if they hd sold x tickets, the owners wud hv got $5x ...if they hd sold (x+30) tickets, the owners wud hv got $(5x+150) which is 30% more than 5x...
thus, u can find value of x and find out the answer..

Hi,

Here are a few DS questions I couldn't solve,


q1. A company enlisted P people to sell 200 knives each, and each salesperson then enlisted P more people to sell 200 knives each. If eveyone sold their 200 knives, what is the value of P?

1) the first P people sold 1/9 of all the knives sold?
2) 14,400 knives were sold in total.

q2. A group of theater owners made an arrangement with an acting company stating that the theater owners would get $5 for every ticket sold. How much did the theater owner earn from the ticket sales?

1) The total revenue was $700
2) If 30 more tickets had been sold, the theater owners would have recvd 30% more money from ticket sales.

q3. Set S consists of n numbers arranged in asc. order. A new set is created as follows: each element in S is increased by a value = that number's place in S. By how much does the mean of the new set > the mean of the original set?

1) set S has 10 elements
2) The sum of elements in the original set is 100.

q4. 3 segments are drawn from opposite corners of a hexagon to form 6 triangles. These segments all bisect each other at pt A. Are the triangles equilateral?

1) All 6 sides are the same length.
2) The 3 segments drawn between the opposite corners are the same length.

Can somebody please help me solve them?




Thanks,
Shipra

Hi
2x-2y=1 with -5 , -4.5 2x-2y=-10-(-9) = -1 not satisfied.
Answer is C

Answer is C.
in both of your examples statement 2 is not satisfied.

2x-2y=1 implies x is greater than y
x/y is graeter than 1 means both x y are positiv or both negative.
if both are positive x is greater than y and if both are -ve x is smaller tha y
for ex to satisf st 2 5,4 or -5,-4 (-5 is smaller tha -4)
-5,-4 type pair can never satisfy st 1.
using both st only type 1 pair is possible . i.e both positive. so answer is C

dude, i hv written -5, -4.5...not -5,-4....since it is not mentioned that x and y MUST be integers...so the first condition is satisfied in all cases...
the answer, once again, has to be E.

u are right...answer is E..
all conditions are satisfied for both the solutions (-1,-1.5) and (5,4.5)

Answer is C.
in both of your examples statement 2 is not satisfied.

2x-2y=1 implies x is greater than y
x/y is graeter than 1 means both x y are positiv or both negative.
if both are positive x is greater than y and if both are -ve x is smaller tha y
for ex to satisf st 2 5,4 or -5,-4 (-5 is smaller tha -4)
-5,-4 type pair can never satisfy st 1.
using both st only type 1 pair is possible . i.e both positive. so answer is C

I got this problem wrong in GMAT prep.

Q) Are x & y both positive ?

(1) 2x - 2y = 1
(2) x/y > 1

The correct answer is 'C'.

My answer is 'E' and explanation as follows.
when x = 3.5 and y = 3
then both conditions are satisfied. What if x = 0.45 and y = -0.05, even then both conditions are satisfied..

Can anyone explain why 'C' is the right answer

u are right...answer is E..
all conditions are satisfied for both the solutions (-1,-1.5) and (5,4.5)

I got this problem wrong in GMAT prep.

Q) Are x & y both positive ?

(1) 2x - 2y = 1
(2) x/y > 1

The correct answer is 'C'.

My answer is 'E' and explanation as follows.
when x = 3.5 and y = 3
then both conditions are satisfied. What if x = 0.45 and y = -0.05, even then both conditions are satisfied..

Can anyone explain why 'C' is the right answer

Let MRSP is M . Sellinng price is S regular price is S. Now the question is Is S less than 50% of R
St 1 R=60% of M=60%of 2000= 1200. We have no idea on S. S could 1000,or 400. Nothing can be concluded
St2 S=R-601 =1200-601=599. Using st1 also.
We can say S=599 and R=1200. this is less than 50% of R. So answer is C
However theer is a twist. in st 1 R is roundede to 60%. Normally for G MAT purpose we shld ignire this and proceed as if it is 60%.
Since the anwer is close which can change the answer whether is is 60.2% or 59.8%. In that case answer is E.

Hi Sriram.. You are awesome !! you got it right.. Its one of the question from the manhattan test.. The answer was E.. but i marked as C.. so by what you in my GMAT test I should mark C.. right ? Thanks so much for answering..

All of the furniture for sale at Als Discount Furniture is offered for less than the manufacturers suggested retail price (MSRP). Once a year, Als holds a clearance sale. If Jamie purchased a certain desk during the sale, did she get a discount of more than 50% of Als regular price for the desk?

(1) Als regular price for the desk is 60%, rounded to the nearest percent, of the MSRP of $2000.

(2) The sale price was $601 less than Als regular price for the desk.

Guy's.. what do you think is the answer ??

Let MRSP is M . Sellinng price is S regular price is S. Now the question is Is S less than 50% of R
St 1 R=60% of M=60%of 2000= 1200. We have no idea on S. S could 1000,or 400. Nothing can be concluded
St2 S=R-601 =1200-601=599. Using st1 also.
We can say S=599 and R=1200. this is less than 50% of R. So answer is C
However theer is a twist. in st 1 R is roundede to 60%. Normally for G MAT purpose we shld ignire this and proceed as if it is 60%.
Since the anwer is close which can change the answer whether is is 60.2% or 59.8%. In that case answer is E.

Q.10.

we have
x2+3x+c = (x+a)(x+b)
= x2+(a+b)x+ab
hence,
3=a+b
c=ab
using st.1,
when a=1,
3=1+b
b=2
hence, c=2

using st.2,
when b=2,
3=a+2
a=1
hence,
c=2
thus, answer is D.


Q.13.
i guess the answer is C. they might have given the wrong answer because in my opinion, it is impossible to find whether d1/r1 is greater than d2/r2 without knowing relation between d1 and d2, r1 and r2...

Q.16.
the question can be simplified as :

.2n > .1(n+.5)

using st.1,
when n=.05,
lhs = .01
rhs = .055
lhs< rhs
so st.1 is sufficient

using st.2,
when n=.02,
lhs = .004
rhs = .052
lhsrhs
so st.2 is nt sufficient
so answer is A.

I think the answer for 10. is D, for 13 is D and for 16 its C.. can you let us know the correct answers given !!! Thanks..

All of the furniture for sale at Als Discount Furniture is offered for less than the manufacturers suggested retail price (MSRP). Once a year, Als holds a clearance sale. If Jamie purchased a certain desk during the sale, did she get a discount of more than 50% of Als regular price for the desk?

(1) Als regular price for the desk is 60%, rounded to the nearest percent, of the MSRP of $2000.

(2) The sale price was $601 less than Als regular price for the desk.

Guy's.. what do you think is the answer ??

Q.10.

we have
x2+3x+c = (x+a)(x+b)
= x2+(a+b)x+ab
hence,
3=a+b
c=ab
using st.1,
when a=1,
3=1+b
b=2
hence, c=2

using st.2,
when b=2,
3=a+2
a=1
hence,
c=2
thus, answer is D.


Q.13.
i guess the answer is C. they might have given the wrong answer because in my opinion, it is impossible to find whether d1/r1 is greater than d2/r2 without knowing relation between d1 and d2, r1 and r2...

Q.16.
the question can be simplified as :

.2n > .1(n+.5)

using st.1,
when n=.05,
lhs = .01
rhs = .055
lhs< rhs
so st.1 is sufficient

using st.2,
when n=.02,
lhs = .004
rhs = .052
lhsrhs
so st.2 is nt sufficient
so answer is A.

Q13 : For me answer looks like E
d1/r1 and d1+30/r1+30 . we cannot conclude any thing from this which fraction is greater.

Hi!
I got the following questions wrong ...can someone explain the Correct answers?
------------------------------------------------------------ ---------------------------------
Q10:
If x2 + 3x + c = (x + a)(x + b) for all x, what is the value of c ?
(1) a = 1
(2) b = 2
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is
sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Ans: I chose C, but it is not correct ..?? Why?
------------------------------------------------------------ ---------------------------------
------------------------------------------------------------ --------------------------------- Q13:
Is the number of seconds required to travel d1 feet at r1 feet per second greater than the
number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2.
(2) r1 is 30 greater than r2.
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is
sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Ans: I chose C, but it is not correct ..?? Why?
my reasoning was let d2 = x and r2 = y, then t2 = x/y i.e. time taken to cover d2. Now 1 and 2 say d1 = x+30 and r1 = r2+30 i.e. t1 = (x+30)/(y+30) ..which is same as x/y...so bo the are required to say whether t1 > t2 or not? in this case t1 = t2
But the ans is D??
------------------------------------------------------------ ---------------------------------
Q16:
If n > 0, which is greater, 20 percent of n or 10 percent of the sum of n and 0.5 ?
(1) n < 0.1
(2) n > 0.01
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is
sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Ans: I chose D, but it is not correct ..?? Why?
------------------------------------------------------------ ---------------------------------

Q.10.

we have
x2+3x+c = (x+a)(x+b)
= x2+(a+b)x+ab
hence,
3=a+b
c=ab
using st.1,
when a=1,
3=1+b
b=2
hence, c=2

using st.2,
when b=2,
3=a+2
a=1
hence,
c=2
thus, answer is D.


Q.13.
i guess the answer is C. they might have given the wrong answer because in my opinion, it is impossible to find whether d1/r1 is greater than d2/r2 without knowing relation between d1 and d2, r1 and r2...

Q.16.
the question can be simplified as :

.2n > .1(n+.5)

using st.1,
when n=.05,
lhs = .01
rhs = .055
lhs< rhs
so st.1 is sufficient

using st.2,
when n=.02,
lhs = .004
rhs = .052
lhsrhs
so st.2 is nt sufficient
so answer is A.

Hi!
I got the following questions wrong ...can someone explain the Correct answers?
------------------------------------------------------------ ---------------------------------
Q10:
If x2 + 3x + c = (x + a)(x + b) for all x, what is the value of c ?
(1) a = 1
(2) b = 2
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is
sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Ans: I chose C, but it is not correct ..?? Why?
------------------------------------------------------------ ---------------------------------
------------------------------------------------------------ --------------------------------- Q13:
Is the number of seconds required to travel d1 feet at r1 feet per second greater than the
number of seconds required to travel d2 feet at r2 feet per second?
(1) d1 is 30 greater than d2.
(2) r1 is 30 greater than r2.
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is
sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Ans: I chose C, but it is not correct ..?? Why?
my reasoning was let d2 = x and r2 = y, then t2 = x/y i.e. time taken to cover d2. Now 1 and 2 say d1 = x+30 and r1 = r2+30 i.e. t1 = (x+30)/(y+30) ..which is same as x/y...so bo the are required to say whether t1 > t2 or not? in this case t1 = t2
But the ans is D??
------------------------------------------------------------ ---------------------------------
Q16:
If n > 0, which is greater, 20 percent of n or 10 percent of the sum of n and 0.5 ?
(1) n < 0.1
(2) n > 0.01
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is
sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.
Ans: I chose D, but it is not correct ..?? Why?
------------------------------------------------------------ ---------------------------------

Hi Just to undestand scores
how many questions were correct ,how many were wrong. and what was quant and verbal and total score

Sriram,
I have given the real GMAT twice now (coincidentally the second one just a few hours ago). So I know for a fact that getting number of questions right or wrong is not the only or the most important criteria. What matters a lot is how well you tackle the harder problems....eg: I would much rather attempt 10 hard questions and get 5 wrong rather than tackle 10 easy questions and get 2 wrong. I mean all this is inter-related no doubt because one may argue how can one get a chance to get to the difficult questions if one keeps on goofing the easier ones. But in any case dont get too much rattled by getting questions wrong. The harder ones are meant to induce mistakes. And it wont just happen with you. It will be the case with many fellow GMAT takers.
Regards,
- TTB

Hi Just to undestand scores
how many questions were correct ,how many were wrong. and what was quant and verbal and total score

Hi All,
Note: I had posted a similar question earlier. Please note however that the questions in this attachment are different from the earlier ones.
Attached are some of the questions from GMATPrep that I got wrong. The options marked with the bold black dot in the attachment are mine and are the wrong answers. The options marked by a square blue frame are correct as these are the correct answers marked by the software. However the software does not explain why a particular choice is correct and others are wrong. I will be very grateful if some of you can help justify why the correct choice is actually correct!
Many thanks.
- TheToastedBread

Q1 M managers,D directors T task force m1 is average salary of managers and d1 and t1 are for dircotrs and task force.
2 equations 1.m+d=t 2.mm1+dd1=tt1
Now opttions 1 d1=t1+15000 2 m1=t1-5000
substitute in eqation 2 mt1-5000m+dt1+15000d=t t1
rewrite (m+d)*t1 -5000m+15000d= (m+d)t1 ( because m+d=t)
you get m=3d
you can answer the question so Answer is C
Q2 form a series with (n,r) u get (5,0)/6,11/7,0/8,15/9,8/10,3/11,0/12,23/13,0
u can see the trend use both options u find remaineder is alwaus 0. so Answer is C
Q3. option 1 one country 41 A atleast 10 . assume other four 1,2,3,4. then A will be 24. if u change other four countries to 2,3,4,5 A will get diff answer. So using stamnet alone it cannot be answered. Stament B does not tell you anything. Using both stament as also you have choice of 9(others 4 6 7 and 10(others 457 or 11 (456 for A. So Answer is E
Q4. Using stament 1 xz is even. means atleast one of x or z is even. x is factor of z. if z is odd x ahs to be even. which is not possible becasue x is factor of z. so z must be even.
statment 2 if y is even z has to be even because y is factor of z. Answer is D
Q5 using staemnet1 x5=x4/2 and using stemnet 2 x5=x4/(x4+1).
using together x4=0 or 1 . if x4 is 0 all numbers in the sequence are 0.(is this considered as series ,all being 0's) i am not sure.
if x4=1 x1=8 . Shoul d the anwer be E if we consider all 0's as a series. or anwers is C

Hi Ajay,
Any reason why you have equated both sets of angles (OBC&OCB;) and (BAO&BOA;) with x? I can understand that OBC=OCB and BAO=BOA but why are all the 4 angles equal to each other, i.e: x? In other words, why is OCB = BAO which is what is implied if you treat both angles as x. Thanks.
Best Regards,
- TTB

1.
AB=OC=OB=radius
in triangle BOC, let OBC=OCB=x degrees
hence, BOC=180-2x
in triangle ABO, let BAO=BOA=x degrees

using st.1,
COD=60,
hence, BOC+BOA=120 degrees
hence, 180-2x+x=120
hence, x=60...
st.1 is sufficient
using st.2,
BCO=40..hence, BAO=40
st.2 is also sufficient...
answer is D.

2.
i dunno man :(

3.
using st.1,
the only option that satisfies 530 miles is he drove the x miles in 7 hrs and remaining in 3 hrs...

hence, st.1 is sufficient

using st.2,
u do not know hw much time he took to cover the remaining distance..he cud take 6 hrs for the first part and 2 hrs for the remaining, or 17 hrs for the first and 13 for the second..so on..
so answer is A.

Hi Ajay & Sriram,
Thanks a ton for taking time out to answer the DS questions. If you get a few moments, please can you also try having a go at the set I have attached in Post#191 on Page 20 of this same thread?
http://www.pagalguy.com/forum/gmat-and-related-discussions/20702-gmat-data-sufficiency-discussions-20.html
Many thanks.
Regards,
-TTB

1.
AB=OC=OB=radius
in triangle BOC, let OBC=OCB=x degrees
hence, BOC=180-2x
in triangle ABO, let BAO=BOA=x degrees

using st.1,
COD=60,
hence, BOC+BOA=120 degrees
hence, 180-2x+x=120
hence, x=60...
st.1 is sufficient
using st.2,
BCO=40..hence, BAO=40
st.2 is also sufficient...
answer is D.

2.
i dunno man :(

3.
using st.1,
the only option that satisfies 530 miles is he drove the x miles in 7 hrs and remaining in 3 hrs...

hence, st.1 is sufficient

using st.2,
u do not know hw much time he took to cover the remaining distance..he cud take 6 hrs for the first part and 2 hrs for the remaining, or 17 hrs for the first and 13 for the second..so on..
so answer is A.

Q2
y>=0 what is value of x
option 1 does not lead to anything
option 2 mod(x-3) <= -Y
here y is 0 or positive number. so -y is 0 or -ve number
mod(x-3) cannot take -ve value. so if -y cannot be -ve number. so y=0 implies mod(x-3)=0 implies x=3

FIRST SET

1.
option 1 does not give us any clue.
in option 2, either both n,p>0 or both n,p<0..so option2 is also inconclusive.
using both options together,
n>-1 and np>0, we know n is +ve..hence, p shud also be +ve..
hence, option C.

2.
using option1,
12u = 8y+12
hence, y = (12u-12)/8 = /8 in which case, no definite answer
using option2,
x=12z+12 = 12(1+z)...hence, we know FOR SURE the gcd is 12 in this case since 1+z is an integer...thus, answer is B.

3.
i dunno....even i wud hv marked E..

4.
the answer is B because there is only one combination that satisfies the price to be 130.... 23*2+21*4....try all other possible (23cents, 21cents) to see if u get a sum of 130 anywher (0,1), (0,2), (2,2), (4,4)....etc..

Q3 Eqution of any line is x/a + y/b = 1 slope of the line is -b/a .x intercept is a y intercept is b.
Now line l is x/a1+y/b1=1 slope -b1/a1
line k is x/a2+y/b2=1 slope is -b2/a2
product of slopes is (b1 *b2)/ (a1*a2) product of x intercepts is a1*a2 and product of y intercepts is b1*b2
With both statments we can say that product of slope is -ve.
so Answer is C

Friends,
Attached is a new set of DS questions from the official GMATPrep! The options marked with the bold black dot in the attachment are mine and are the wrong answers. The options marked by a square blue frame are correct as these are the correct answers marked by the software. However the software does not explain why a particular choice is correct and others are wrong. I will be very grateful if some of you can help justify why the correct choice is actually correct!

Many thanks.

- TheToastedBread

1.
AB=OC=OB=radius
in triangle BOC, let OBC=OCB=x degrees
hence, BOC=180-2x
in triangle ABO, let BAO=BOA=x degrees

using st.1,
COD=60,
hence, BOC+BOA=120 degrees
hence, 180-2x+x=120
hence, x=60...
st.1 is sufficient
using st.2,
BCO=40..hence, BAO=40
st.2 is also sufficient...
answer is D.

2.
i dunno man :(

3.
using st.1,
the only option that satisfies 530 miles is he drove the x miles in 7 hrs and remaining in 3 hrs...

hence, st.1 is sufficient

using st.2,
u do not know hw much time he took to cover the remaining distance..he cud take 6 hrs for the first part and 2 hrs for the remaining, or 17 hrs for the first and 13 for the second..so on..
so answer is A.

Friends,
Attached is a new set of DS questions from the official GMATPrep! The options marked with the bold black dot in the attachment are mine and are the wrong answers. The options marked by a square blue frame are correct as these are the correct answers marked by the software. However the software does not explain why a particular choice is correct and others are wrong. I will be very grateful if some of you can help justify why the correct choice is actually correct!

Many thanks.

- TheToastedBread

FIRST SET

1.
option 1 does not give us any clue.
in option 2, either both n,p>0 or both n,p<0..so option2 is also inconclusive.
using both options together,
n>-1 and np>0, we know n is +ve..hence, p shud also be +ve..
hence, option C.

2.
using option1,
12u = 8y+12
hence, y = (12u-12)/8 = /8 in which case, no definite answer
using option2,
x=12z+12 = 12(1+z)...hence, we know FOR SURE the gcd is 12 in this case since 1+z is an integer...thus, answer is B.

3.
i dunno....even i wud hv marked E..

4.
the answer is B because there is only one combination that satisfies the price to be 130.... 23*2+21*4....try all other possible (23cents, 21cents) to see if u get a sum of 130 anywher (0,1), (0,2), (2,2), (4,4)....etc..

Is xy > x2y2?
(1) 14x2 = 3
(2) y2 = 1
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient

u cannot answer the question using either statement alone, that's for sure..if u use both 1&2,

y can either be +1 or -1........similarly, x can either be +sqrt(3/14) or -sqrt(3/14)...

when x=sqrt(3/14), y=1

xy > x2y2

when x=sqrt(3/14), y=-1
x2y2>xy

when x=-sqrt(3/14), y=1
x2y2>xy

when x=-sqrt(3/14), y=-1
xy>x2y2..
hence, in my opinion, answer is E.

Friends,
Attached is a new set of DS questions from the official GMATPrep! The options marked with the bold black dot in the attachment are mine and are the wrong answers. The options marked by a square blue frame are correct as these are the correct answers marked by the software. However the software does not explain why a particular choice is correct and others are wrong. I will be very grateful if some of you can help justify why the correct choice is actually correct!

Many thanks.

- TheToastedBread

Q5 Answer is C
from statment 2 either n and p both are + or both -ve. From statement 1 n+1>0 n cannot be -ve. so 0 or above. From both to gether u can say both n and p are +ve.

Friends,
Attached is a new set of DS questions from the official GMATPrep! The options marked with the bold black dot in the attachment are mine and are the wrong answers. The options marked by a square blue frame are correct as these are the correct answers marked by the software. However the software does not explain why a particular choice is correct and others are wrong. I will be very grateful if some of you can help justify why the correct choice is actually correct!

Many thanks.

- TheToastedBread

Plz note....each '2' denotes the square of previous variable......

Is xy > x2y2?
(1) 14x2 = 3
(2) y2 = 1
A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient

Ans is C. Am i correct?
From (1) we can infer y and z have same sign. Similarly from (2) x and y have same signs. So combining both x, y, z have same sign. So x(y+z) is greater than 0.

Ans is C...

Hi All,
Note: I had posted a similar question earlier. Please note however that the questions in this attachment are different from the earlier ones.
Attached are some of the questions from GMATPrep that I got wrong. The options marked with the bold black dot in the attachment are mine and are the wrong answers. The options marked by a square blue frame are correct as these are the correct answers marked by the software. However the software does not explain why a particular choice is correct and others are wrong. I will be very grateful if some of you can help justify why the correct choice is actually correct!
Many thanks.
- TheToastedBread

I am sorry..small modification in question
1. Is Sqrt = 3-x

A) x is not equal to 3
B) x*(MOD x) < 0

Hi mohanraaz

my analysis would be like this:
We have to answer in yes or no!!
see option A":
This says x!=3. But it give no info on the sign of x.Hence insufficient.
See option B:
x is -ve. Hence +or- (x-3)=3-x
substitute -x
+ or- (-3-x)=+or-(x+3)
Hence they are not equal

B alone is sufficient to answer.

Please correct me if i'm wrong.

HI All,
Can any one sugggest a way to improve in DS? Currently doing terrible in it!!!??:. Please consider this as an sos!!!!


Siddhartha.

Hi All,
A friend lent me a torn, tatterred Kaplan 800. Just my good luck that it has 2 pages missing and very important ones too!
Can someone who's got the book, please post the following data sufficiency problems from Kaplan 800?
Pg 373 --> Q.4 and Q.5
Pg 377 --> Q.8 and Q.9
I am sure others on this forum (not specifically suffering from the problem I do) will also prefer having a crack at 4 good Data suff. questions!
Many thanks.
Regards,
- TTB

Guys!

A very simple question;

What's the value of X?
1. X(X+1) = 0
2. X^2 = -X



Cheers,
Sumit :neutral:

answer is E....
cuz both options boil down to the same expression...i.e. X2 + X=0..

C?

x*(x+1)=0 x= 0 or 1

x2=-x x=0 or -1

using both ans is 0 . so C

Sorry for the typo. please read the first expression as "X(X+1)"


Cheers,
Sumit

winkswhoofwhoof Says

How does E look?

C?

x*(x-1)=0 x= 0 or 1

x2=-x x=0 or -1

using both ans is 0 . so C

Guys!
A very simple question;
What's the value of X?
1. X(X-1) = 0
2. X^2 = -X
Cheers,
Sumit :neutral:

How does E look?

Guys!

A very simple question;

What's the value of X?
1. X(X+1) = 0
2. X^2 = -X



Cheers,
Sumit :neutral:

Yea Answer is B
Read the question carefully. It was asked morning session ONLY. Using statement B 7/8 didi attend afetr noon sesion .remaining 1/8 did not attend after noon session. So they attended morning session only.

so assuming 'x' as total members....morning session=x/8....still we dont get a integer number..jst a ratio

winkswhoofwhoof Says

howz E?........seems suitable as no data is given

Yea Answer is B
Read the question carefully. It was asked morning session ONLY. Using statement B 7/8 didi attend afetr noon sesion .remaining 1/8 did not attend after noon session. So they attended morning session only.

Actual answer is B.
this question i got in GMATPREP. I too answered E because no way we can determine from the info given. I got 710 in GMATPREP at last ,and i got this question between q.no 20 and 25.

But i could nt understand how it can be B

One more DS.
A certain 1 day seminar consisted a morning session and an afternoon session. If each of ppl attending seminar attended at least one seminar, how many attended morning session only.
A. 3/4 people attended both seminars
B. 7/8 attended afternoon session

howz E?........seems suitable as no data is given

One more DS.
A certain 1 day seminar consisted a morning session and an afternoon session. If each of ppl attending seminar attended at least one seminar, how many attended morning session only.
A. 3/4 people attended both seminars
B. 7/8 attended afternoon session

Hi Answer is D
with statement A X is not equal to 3
if x>3 then 3-x is -ve and sqrt(sqrt(x-3) cnnot take -ve value.
if x is less than sqrt (sqrt(x-3) is an imaginary number ,on the other hand 3-x is a real number.
using the statement A alone we can conclude that both are not equal.
Now using staement B alosne. we can say x is a -ve number
so LHS is an imaginary number and RHS is a real number. so both are not equal.
both are equal only when x=3

It is SQRT , its NOT SQRT

I am sorry..small modification in question
1. Is Sqrt = 3-x

A) x is not equal to 3
B) x*(MOD x) < 0

Hi Answer is D
with statement A X is not equal to 3
if x>3 then 3-x is -ve and sqrt(sqrt(x-3) cnnot take -ve value.
if x is less than sqrt (sqrt(x-3) is an imaginary number ,on the other hand 3-x is a real number.
using the statement A alone we can conclude that both are not equal.
Now using staement B alosne. we can say x is a -ve number
so LHS is an imaginary number and RHS is a real number. so both are not equal.
both are equal only when x=3

If x is a -ve integer, as derived form second option, then if you substitute the value of x as (-x) in SQRT(sqr(x-3)) will be +ve(-x-3) which is same as (3-(-x)).

answer is B.
But how can we say if SQRT is = 3-x ??

Is the answer B? I mean we can tell from the B option alone that if x is negative then sqrt of sqr(-x-3) will be same as (3-(-x)).

I am sorry..small modification in question
1. Is Sqrt = 3-x

A) x is not equal to 3
B) x*(MOD x) < 0

I got this question wrong in GMATPREP. Even after seeing the answer, i couldnt get how it is.
Can u pls take a look and try and answer - with explaination

I took GMATPREP and there are some questions which were wrong. I would like them post them here. Try, answer and explain why it it is the answer.

DS:

1. Is Sqrt (x-3) = 3-x

A) x is not equal to 3
B) x*(MOD x) < 0

if sqrt(x-3)=3-x, then x-3=9-6x+x2
x2-7x+12=0
so question is askin whether x2-7x+12 = 0
which is possible only if x=3 or x=4

so A is nt sufficient to answer because x can be equal to 4 also...
st.B tells us that x is a -ve number since x Mod(x)<0...hence, x is nt equal to either 3 or 4...
so answer is B.

I got this question wrong in GMATPREP. Even after seeing the answer, i couldnt get how it is.
Can u pls take a look and try and answer - with explaination

I took GMATPREP and there are some questions which were wrong. I would like them post them here. Try, answer and explain why it it is the answer.

DS:

1. Is Sqrt (x-3) = 3-x

A) x is not equal to 3
B) x*(MOD x) < 0

ATTN all!!!
ZERO is a multiple of any number and it is included in the list of multiples of a number...i verified this while giving the Full length test of Kaplan Premier Edition in the book....

guyz ne suggestions for da DS...especialy for questions like:

iz m+z>0

1) m-3z>0
2) 4z-m>0


i chose "E" which kinda looked obvoius ...

any suggestions while guessing..or any other trciks...i usually stumble upon DS
thx

This question. using bot staeemnts
add both u get z>0. now using staement 1 u willget m>3z means m is also positive. so m+z >0.. Anw is C

guyz ne suggestions for da DS...especialy for
i chose "E" which kinda looked obvoius ...

any suggestions while guessing..or any other trciks...i usually stumble upon DS
thx

Well I think that the answer is C.

Expln:

Suppose we have "M" no. of managers and "D" no. of Directors, with the avg salary of the group (M+D) = t.

So with choice 1 => Avg salary of managers = t-5; NOT SUFFICIENT
and with choice 2 => avg slary of Directors = t+15; NOT SUFFICIENT

Now with choice 1 and choice 2, together:

Total Salary for the group = (Total salary of Managers) + (Total salary of directors)

(M+D)t = M(t-5) + D(t+15)
or, (Mt + Dt) = (Mt + Dt - 5M + 15D)
or, 5M = 15D
or M/D = 3;

Hence, sufficient.

Answer: C

Cheers,
Sumit

guyz ne suggestions for da DS...especialy for questions like:

iz m+z>0

1) m-3z>0
2) 4z-m>0


i chose "E" which kinda looked obvoius ...

any suggestions while guessing..or any other trciks...i usually stumble upon DS
thx