|x| + |y| = 32 ; what is the value of xy ?
1. -4x - 12y = 0
2. |x| -|y| = 16
I solved it as follows -
Statement 1:
x = -3y
Original Statement :
x + y = 32 Using statement 1. y = -16
-x +y = 32 Using Statement 1. y = 8
x - y = 32 Using Statement 2. y = -8
And so 1 is not sufficient . However the Original Answer is A
They do not consider all 3 cases that I did. Is it wrong to consider all the cases as I did ?
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
Data Sufficiency questions 700 level - problem
This topic has expert replies
-
ashwinhirawat
- Newbie | Next Rank: 10 Posts
- Posts: 1
- Joined: Wed Jan 18, 2012 11:25 am
-
hackscript
- Newbie | Next Rank: 10 Posts
- Posts: 2
- Joined: Thu Apr 12, 2012 8:57 am
Considering (1)
x=-3y, so if x is positive y is negative
Considering x positive: x-y=32 and x=-3y solving, y=-8 and x=24
Considering x negative: -x+y=32 and x=-3y solving, y=8 and x=-24
The product is the same so (1) is suf
Considering (2)
Adding both equations, x=24 or x=-24 and so y=8 or y=-8
Can't no if product is 8*24 or -8*24
so (2) is insuf
Answer: A
x=-3y, so if x is positive y is negative
Considering x positive: x-y=32 and x=-3y solving, y=-8 and x=24
Considering x negative: -x+y=32 and x=-3y solving, y=8 and x=-24
The product is the same so (1) is suf
Considering (2)
Adding both equations, x=24 or x=-24 and so y=8 or y=-8
Can't no if product is 8*24 or -8*24
so (2) is insuf
Answer: A
-
GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
