DATA SUFFICIENCY ALL INTEGERS

Expert replies

francoisph: Master | Next Rank: 500 Posts; Posts: 124; Joined: Sun Mar 07, 2010 3:15 pm; Thanked: 1 times

by francoisph » Wed Jun 02, 2010 6:32 am

hi,

please could you explain below?

for all integers n, n^*=n(n-1)
What is the value of X^*?
1) X^*=X
2) (X-1)^*=X-2

Star * symbol???

Like this post

Source: Beat The GMAT — Problem Solving | Wed Jun 02, 2010 6:32 am

liferocks: Legendary Member; Posts: 576; Joined: Sat Mar 13, 2010 8:31 pmFollowed by: 1 member; Thanked: 97 times

by liferocks » Wed Jun 02, 2010 6:35 am

From 1
X^*=X or x(x-1)=x
or x^2 -2x=0
or x(x-2)=0

so x can be either 0 or 2..not sufficient

From 2
(X-1)^*=X-2
or (x-1)(x-2)=x-2
or (x-2)^2=0 so x=2..sufficient

Ans option B

please post DS question under DS sub-forum.

"If you don't know where you are going, any road will get you there."
Lewis Carroll

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 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