GMAT Problem Solving Discussions

How many different ways can 3 cubes be painted if each cube is painted one color and only the 3 colors red, blue and green are available?( Order is not considered , for example , green,green, blue is considered the same as green, blue, green.)

Please post the explanation. Thanks In advance.


I think the ans for this should be 3^3 ie each cube can be painted in 3 colors. What is the OA ?


Hey ...if order does nt matter ...i dont think it can be 3^3 ..

All that matters is choosing d diff set of colors ..

i.e choose 1 out of 3 colors OR 2 out of 3 colors OR 3 out of 3 colors..

i.e 3C1 + 3C2 + 3C3 = 3+3+1 =7 ways ...

If the drama club and movie club are combined what % of the combined membership will be male?
1) Of the 16 members of the drama club, 15 are male.
2) Of the 20 members of the music club , 10 are male.

Well I came across this question in one test and the answer as mentioned is E i.e Statement 1 and 2 are not sufficient to answer this question.

Can some one explain me why is it E ?

If the drama club and movie club are combined what % of the combined membership will be male?
1) Of the 16 members of the drama club, 15 are male.
2) Of the 20 members of the music club , 10 are male.

Well I came across this question in one test and the answer as mentioned is E i.e Statement 1 and 2 are not sufficient to answer this question.

Can some one explain me why is it E ?

I think bcos in statement 2, the number of members in music club and not movie club is given. Not sure though if its a typo. Pls confirm.

Sorry its a typo...In satement 2 it should be movie club

Hey the reason why it is E is because in the question they havent mentioned the number of people who are in both the clubs. That means this question can only be solved assuming the there is no intersection between the two clubs. I hope you got my point.

In case, Please do let me know I will explain it in a better way.

If the drama club and movie club are combined what % of the combined membership will be male?
1) Of the 16 members of the drama club, 15 are male.
2) Of the 20 members of the movie club , 10 are male.

Well I came across this question in one test and the answer as mentioned is E i.e Statement 1 and 2 are not sufficient to answer this question.

Can some one explain me why is it E ?

Hey the reason why it is E is because in the question they havent mentioned the number of people who are in both the clubs. That means this question can only be solved assuming the there is no intersection between the two clubs. I hope you got my point.

In case, Please do let me know I will explain it in a better way.


Hi!

The answer is E as explained by virus_rocks.
Cause we only the figures for Drama and Movie club, there is no info about the common people in both the groups.

And, arnabray07, one reuqest- can you ple post the further DS ques in the following thread:
http://www.pagalguy.com/discussions/gmat-data-sufficiency-discussions-25020702

Individual threads exist for PS, DS, CR, RC and SC.
So ple post the question in relevant thread.

thankyou.
and hope your doubt is cleared.

Regards,
Neha

GMAT educational series

1) Before joining anybody for GMAT please make it sure that he has taken the GMAT himself.

2) Ask him to show his GMAT SCORE on the official link
http://www.pearsonvue.com/entry/gmat/vosr.jsp?regID=218113741&key;=79ca06cee3ff2d2de6e1e15abc2f05748190d50e

by supplying his authentication code..

3) Take a demo class from him.

4) Do not pay the whole fees upfront so that you reserve the right to leave the institute at any point of time you are not satisfied.

Hi Guys,

I have 1 problem here .Is it possible for someone to tell me the solution to this

if x/3 is an integer each of the following must be an integer EXCEPT :

(x+6)/6

(x-9)/3

(x+9)/3

8x/24

(x^4 - 81)/81

I got stuck between answer choices A and E

All help is appreciated .

Hi Guys,

I have 1 problem here .Is it possible for someone to tell me the solution to this

if x/3 is an integer each of the following must be an integer EXCEPT :

(x+6)/6

(x-9)/3

(x+9)/3

8x/24

(x^4 - 81)/81

I got stuck between answer choices A and E

All help is appreciated .


will go with A- for this we may or may not get an integer always

choice E becomes (x/3)^4 -1. since x/3 is an integer so the expression will give an integer
Hi Guys,

I have 1 problem here .Is it possible for someone to tell me the solution to this

if x/3 is an integer each of the following must be an integer EXCEPT :

(x+6)/6

(x-9)/3

(x+9)/3

8x/24

(x^4 - 81)/81

I got stuck between answer choices A and E

All help is appreciated .



Whenever you get such ques, always take two values for x and check for each option. the option which doesn't give the integer value, is your answer. In this case take x=12 and 3. on checking for all 5 options. we see it's only A for which the value doesn't come out to be integer. and yes as kp1811 said- E can be simplified to (x/3)^4-1. that solves the problem.


Regards,
Neha

Thanks Neha and kp

Hey ...if order does nt matter ...i dont think it can be 3^3 ..

All that matters is choosing d diff set of colors ..

i.e choose 1 out of 3 colors OR 2 out of 3 colors OR 3 out of 3 colors..

i.e 3C1 + 3C2 + 3C3 = 3+3+1 =7 ways ...



I have another way to solve this ...

1) All have different Colors : RBG : Only one possibility

2) 2 have same colour & 3rd is different color :

RRB, RRG, BBG, BBR, GGR, GGB

3) ALL HAVE same colour

GGG , BBB, RRR

Total is 10 possibilities .... let me know if this is correct ans.

I need to know where I am going wrong in arriving at the soln :-

Q: (x^2 + 4x + 4) / (x^2 - 4) = 3 Find X?

Options : 4, 2 , 0, -2, -4

Sol : X^2 + 4X + 4 = 3x^2 - 12

2X^2 - 4X - 8 = 0

X^2 - 2X -4 = 0

I could solve only upto here ... Ans is 4. above Eqn doesnot satisfy x=4 but, original given expression satisfies x=4 ....

very confusd ...pls help.....

General Question :

How do you find the number of terms in(a1+a2+a3....an)^m ?

I need to know where I am going wrong in arriving at the soln :-

Q: (x^2 + 4x + 4) / (x^2 - 4) = 3 Find X?

Options : 4, 2 , 0, -2, -4

Sol : X^2 + 4X + 4 = 3x^2 - 12

2X^2 - 4X - 8 = 0

X^2 - 2X -4 = 0

I could solve only upto here ... Ans is 4. above Eqn doesnot satisfy x=4 but, original given expression satisfies x=4 ....

very confusd ...pls help.....


If u solve the quadratic eq u will get (x+2)(x+2)/(x-2)(x+2)=3. Solving this further will give 2x=8, x=4. I hope this clears your doubt

Yes it has to be (E)

Nitin. Says
If u solve the quadratic eq u will get (x+2)(x+2)/(x-2)(x+2)=3. Solving this further will give 2x=8, x=4. I hope this clears your doubt


Cancelling x+2 on both Num & Deno is possible only when X!=-2.When x = -2 this should nt be done.

Solving we get x=4

Thanks Deepak, Nitin and lifeis+ .

Factorizing seems correct way here rather than the one I was following.

I need to know where I am going wrong in arriving at the soln :-

Q: (x^2 + 4x + 4) / (x^2 - 4) = 3 Find X?

Options : 4, 2 , 0, -2, -4

Sol : X^2 + 4X + 4 = 3x^2 - 12

2X^2 - 4X - 8 = 0

X^2 - 2X -4 = 0

I could solve only upto here ... Ans is 4. above Eqn doesnot satisfy x=4 but, original given expression satisfies x=4 ....

very confusd ...pls help.....


Your approach is correct.However the mistake was -12+-4=-16 instead of -8

I'm Quoting somebody's ques, can someone ple explain how to find this one?


General Question :
How do you find the number of terms in(a1+a2+a3....an)^m ?