A set of data consists of the following 5 numbers: 0,2,4,6, and 8. Which two numbers, if added to create a set of 7 numbers, will result in a new standard deviation that is close to the standard deviation for the original 5 numbers?
A) -1 and 9
B) 4 and 4
C) 3 and 5
D) 2 and 6
E) 0 and 8
solve this and give the explanation
Regards,
Vijay
try this
Fox jeans regularly sell for $15 a pair and Pony jeans regularly sell for $18 a pair. During a sale these regular unit prices are discounted at different rates so that a total of $9 is saved by purchasing 5 pairs of jeans: 3 pairs of Fox jeans and 2 pairs of Pony jeans. If the sum of the two discounts rates is 22 percent, what is the discount rate on Pony jeans?
(A) 9%
(B) 10%
(C) 11%
(D) 12%
(E) 15%
give the explanation as well
say fox jeans discount % = fd; pony jean discount % = pd
actual price * discount % = actual amount
actual discount of fox jeans + actual discount pony jeans = $ 9
3*15*fd+2*18*pd= $ 9
also fd+Pd=0.22 (as per question)
if you solve this Equation, pd= 0.1 i.e 10%
Ans is B
say fox jeans discount % = fd; pony jean discount % = pd
actual price * discount % = actual amount
actual discount of fox jeans + actual discount pony jeans = $ 9
3*15*fd+2*18*pd= $ 9
also fd+Pd=0.22 (as per question)
if you solve this Equation, pd= 0.1 i.e 10%
Ans is B
hi,
Im convinced with ur explanation. but is there a shorter way to solve this question by means of POE?
Dont know....I personally would not try POE esp in calculations. I would always go wrong ...
A set of data consists of the following 5 numbers: 0,2,4,6, and 8. Which two numbers, if added to create a set of 7 numbers, will result in a new standard deviation that is close to the standard deviation for the original 5 numbers?
A) -1 and 9
B) 4 and 4
C) 3 and 5
D) 2 and 6
E) 0 and 8
solve this and give the explanation
Regards,
Vijay
IMO Ans D ...question is to keep stdev at the same and not to lower it ...
For above data : avg is 4 ...
stdev = sq root (variance)
For the original 5 nos, variance = 2 / 5 = 8 ..
So variance of 7 nos should be closest to 8 i.e total of diff of squares = 56 ...
So diff of squares of additional 2 nos should be closest to 16 ...
Option wise :
1) 50
2) 0
3) 2
4) 8
5) 32
Closest to 16 among 5 options is D
IMO Ans D ...question is to keep stdev at the same and not to lower it ...
For above data : avg is 4 ...
stdev = sq root (variance)
For the original 5 nos, variance = 2 / 5 = 8 ..
So variance of 7 nos should be closest to 8 i.e total of diff of squares = 56 ...
So diff of squares of additional 2 nos should be closest to 16 ...
Option wise :
1) 50
2) 0
3) 2
4) 8
5) 32
Closest to 16 among 5 options is D
yes dude u r right OA is d
A group of 8 friends want to play doubles tennis. How many different ways can the group be divided into 4 teams of 2 people?
A. 420
B. 2520
C. 168
D. 90
E. 105
solve this and give the explanation
A. 420
B. 2520
C. 168
D. 90
E. 105
solve this and give the explanation
A serial set consists of N bulbs. The serial set lights up only if all the N bulbs are in working condition. Even if one of the bulbs fails then the entire set fails. The probability of a bulb failing is x. What is the probability of the serial set failing?
solve this and give explanation
solve this and give explanation
A group of 8 friends want to play doubles tennis. How many different ways can the group be divided into 4 teams of 2 people?
A. 420
B. 2520
C. 168
D. 90
E. 105
solve this and give the explanation
let us say the team members are A,B,C,D,E,F,G,H
1st team = 8C2 ways
2nd team = 6C2 ways
3rd team = 4C2 ways
4th team = 2C2 ways
Now, it does not matter which team is selected when i.e we are not interested in arranging the teams as per their selection but we gotta only select them ..hence divide by 4!
So , total ways = 8C2 * 6C2 * 4C2 * 2C2 / 4! = 105 ..option E
A serial set consists of N bulbs. The serial set lights up only if all the N bulbs are in working condition. Even if one of the bulbs fails then the entire set fails. The probability of a bulb failing is x. What is the probability of the serial set failing?
solve this and give explanation
P(failure) =x
Hence, p(success) = 1-x
Serial set works only if each of the bulbs works.
i.e p(success of serial set) = (1-x)^n
Hence, p(failure of serial set) = 1-p(success)
= 1 - (1-x)^n
try this
Fox jeans regularly sell for $15 a pair and Pony jeans regularly sell for $18 a pair. During a sale these regular unit prices are discounted at different rates so that a total of $9 is saved by purchasing 5 pairs of jeans: 3 pairs of Fox jeans and 2 pairs of Pony jeans. If the sum of the two discounts rates is 22 percent, what is the discount rate on Pony jeans?
(A) 9%
(B) 10%
(C) 11%
(D) 12%
(E) 15%
give the explanation as well
Is the answer B?
if the answer is right then will give the explaination
vpitc Saysya u r right OA is b
Alright i kinda back solved it and used the POE to eliminate the answers.
will give the explanation in that way only.
First of all i eliminated answer choices A 9 is given in the ques.
In any (most of) math ques, 3 choices-
1) the option which says-it cannot be determined,
2)the values which are given in ques if they repeat in answer choices (as in this ques 9), and
3) the values which can be obtained from the values given in the ques
these all can be eliminated with certainty.
Now, from the given ques-
Total Cost of the jeans before discount= ($15*3)+($18*2)=$81
Total cost of the jeans after the discount= $81-$9=$72
D1 is the discount rate of Fox jeans, D2 is Discount rate of pony Jeans
And D1% is the discount % of Fox jeans and D2% is the discount% of pony jeans.
D1 %+ D2%= 22%
D1 + D2=$9
Now use the options, start with B-10%
If D2% is 10% then D1% should be 12%
P2 is $18, after discount of 10% the new P2 will be $16.2
P1 is $15, after discount of 12% the new P1 will be $13.2
To confirm the D2% is 10% and D1% is 12%
Put the values and check that the total price paid the customer comes out to be $72 or not.
Total cost of the jeans after the discount= ($13.2*3)+($16.2*2)=$72.
This shows that D2% is 10% and D1% is 12%.
Hence the Answer is B.
Incase this wouldn't have come to $72, then I would have used the other answer choices C,D and E to check.
Hope this clears your doubt.
Regards,
Neha
let us say the team members are A,B,C,D,E,F,G,H
1st team = 8C2 ways
2nd team = 6C2 ways
3rd team = 4C2 ways
4th team = 2C2 ways
Now, it does not matter which team is selected when i.e we are not interested in arranging the teams as per their selection but we gotta only select them ..hence divide by 4!
So , total ways = 8C2 * 6C2 * 4C2 * 2C2 / 4! = 105 ..option E
Hi,
Can you please explain why we need to divide by 4!. The total number of possible selections is given by 8C2 * 6C2 * 4C2 * 2C2 , but how does it include all possible arrangements as well?
Regards,
Shamim
Hi,
Can you please explain why we need to divide by 4!. The total number of possible selections is given by 8C2 * 6C2 * 4C2 * 2C2 , but how does it include all possible arrangements as well?
Regards,
Shamim
Lets take an eg of 4 ppl A,B,C,D to select 2 teams of 2 ppl
Possibilities :
1) AB & CD
2) AC & BD
3) AD & BC ....just 3 poss ....
actually when we do 4C2 * 2C2 we get 6 teams ....but when we select first team , we have automatically selected the other team ...
I mean it does not matter whether it is AB and CD or CD and AB ...
Hence, for 2 teams, it is total divided by 2 ..
For 3 teams, it is divided by 3 ..
For 4 teams it is divided by 4 ...
Hence, total = 8C2 * 6C2 * 4C2 * 2C2 / (4*3*2)
= 8C2 * 6C2 * 4C2 * 2C2 / 4! ..
scratchy on the explanation...but i hope it clears the doubt ...
Nice explanation!!
try this,
As a part of a game, four people each much secretly chose an integer between 1 and 4 inclusive. What is the approximate likelihood that all four people will chose different numbers?
Is the ans 3/32 for the above problem?
try this,
As a part of a game, four people each much secretly chose an integer between 1 and 4 inclusive. What is the approximate likelihood that all four people will chose different numbers?
Answer: 3/32?
A set of data consists of the following 5 numbers: 0,2,4,6, and 8. Which two numbers, if added to create a set of 7 numbers, will result in a new standard deviation that is close to the standard deviation for the original 5 numbers?
A) -1 and 9
B) 4 and 4
C) 3 and 5
D) 2 and 6
E) 0 and 8
solve this and give the explanation
Regards,
Vijay
Is the answer to this question D?
try this,
As a part of a game, four people each much secretly chose an integer between 1 and 4 inclusive. What is the approximate likelihood that all four people will chose different numbers?
P = 4! / 4^4 = 3/32
in other words probability of ind selection is p = 1 * 3/4 * 2/4 * 1/4 = 3/32
While on a straight road, car
X and car Y are traveling at different constant rates. If car X is now 1 mile ahead of car Y, how many minutes from now
will car X be 2 miles ahead of car Y ?
(1) Car X is traveling at 50 miles per hour and car Y is traveling at 40 miles per hour.
(2) 3 minutes ago car X was 1/2 mile ahead of car Y.
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.
Even from statement (1), one cannot conclude on relative speed as one does not know the direction in which the cars are moving( same or opposite)
St(2) 3 min ago Car X was 1/2 mile ahead of car Y, considering both are travelling at constant rates, the rel distance in next 3 min will be 1/2 more mile. so in 6 min they are 1 mile apart i.e right nowSo 2 miles in 12 min. I don't know if this logic is going right.
Please comment/ explain the right ans