Value of X - A DS problem. - The Beat The GMAT Forum - Expert GMAT Help & MBA Admissions Advice

Value of X - A DS problem.

Expert replies

mah927: Newbie | Next Rank: 10 Posts; Posts: 7; Joined: Sun Oct 19, 2008 5:27 pm

by mah927 » Wed Feb 24, 2010 6:38 pm

What is the value of x ?
(1) x^2 + y^2 = 25
(2) xy = 12

OA is E. I thought it is C. Since you have two equations. Am I totally missing something? Thanks in advance for help.

Like this post

Source: Beat The GMAT — Data Sufficiency | Wed Feb 24, 2010 6:38 pm

ajith: Legendary Member; Posts: 1275; Joined: Thu Sep 21, 2006 11:13 pmFollowed by: 2 members; Location: Arabian Sea; Thanked: 125 times

by ajith » Wed Feb 24, 2010 10:34 pm

mah927 wrote:What is the value of x ?
(1) x^2 + y^2 = 25
(2) xy = 12

OA is E. I thought it is C. Since you have two equations. Am I totally missing something? Thanks in advance for help.

x^2 + y^2 = 25
xy = 12

x^2+y^2 +2xy = 49

(x+y)^2 = 49

x^2+y^2 -2xy = 1

(x-y)^2 = 1

x= -3 y = -4 and x =4 y = 3 both satisfy this, no unique value for x hence E

Always borrow money from a pessimist, he doesn't expect to be paid back.

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

560 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review