If x and y are integers, what is the ratio of 2x to y?
8x3 = 27y3 (read x cube, y cube)
4x2 = 9y2 (read x square, y square)
Need help with this data sufficiency problem
This topic has expert replies
-
- Newbie | Next Rank: 10 Posts
- Posts: 3
- Joined: Sun Feb 05, 2012 6:40 am
- Thanked: 1 times
-
- Newbie | Next Rank: 10 Posts
- Posts: 6
- Joined: Sun Jun 05, 2011 10:51 am
- Thanked: 3 times
I think the answer is A. we get 2x=3y from 1 which means the ratio is 3:1. for 2 since its a square we are not sure whether its positive or negative. it can be 2x=3y or -2x=3y.
targetthegmat wrote:If x and y are integers, what is the ratio of 2x to y?
8x3 = 27y3 (read x cube, y cube)
4x2 = 9y2 (read x square, y square)
-
- Legendary Member
- Posts: 1085
- Joined: Fri Apr 15, 2011 2:33 pm
- Thanked: 158 times
- Followed by:21 members
2x/y?targetthegmat wrote:If x and y are integers, what is the ratio of 2x to y?
8x3 = 27y3 (read x cube, y cube)
4x2 = 9y2 (read x square, y square)
st(1) 8x^3=27y^3 implies (2x)^3=(3y)^3 or 2x=3y which is Sufficient to answer 2x/y, as 2x/3y=1 and 3*(2x/3y)=3
st(2) 4x^2=9y^2 implies (2x)^2=(3y)^2 or |2x|=|3y| Not Sufficient
a
Success doesn't come overnight!
GMAT/MBA Expert
- Anurag@Gurome
- GMAT Instructor
- Posts: 3835
- Joined: Fri Apr 02, 2010 10:00 pm
- Location: Milpitas, CA
- Thanked: 1854 times
- Followed by:523 members
- GMAT Score:770
(1) 8x^3 = 27y^3targetthegmat wrote:If x and y are integers, what is the ratio of 2x to y?
8x3 = 27y3 (read x cube, y cube)
4x2 = 9y2 (read x square, y square)
(2x)^3 = (3y)^3
Taking cube root on both sides,
2x = 3y
2x : y = 3 : 1; SUFFICIENT.
(2) 4x² = 9y²
Taking square root on both sides,
±2x = 3y; NOT sufficient.
The correct answer is A.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)
Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/
-
- Newbie | Next Rank: 10 Posts
- Posts: 1
- Joined: Sat Apr 27, 2013 12:31 pm
Hi, I have a question. I had picked (E) because I took the scenario of x and y being set to 0. Is it incorrect to use 0 as a value to plug in for x and y? Can we not take zero for both because x and y are two different variables?