• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• Reach higher with Artificial Intelligence. Guaranteed
Now free for 30 days

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

## Princeton Question

This topic has 2 member replies
f2001290 Master | Next Rank: 500 Posts
Joined
10 Mar 2007
Posted:
400 messages
Followed by:
1 members
1

#### Princeton Question

Sun May 06, 2007 1:05 am
For integers a and b, if sqrt(a^3 - a^2 - b) = 7, what is the value of a ?

1. a^2 - a = 12
2. b^2 - b = 2

Please explain the solution for this problem.
Attachments

f2001290 Master | Next Rank: 500 Posts
Joined
10 Mar 2007
Posted:
400 messages
Followed by:
1 members
1
Sun May 06, 2007 8:02 pm
Jay Hawk

Did you score a 800 in GMAT?

You don't leave any questions in PS unanswered

jayhawk2001 Community Manager
Joined
28 Jan 2007
Posted:
789 messages
Followed by:
1 members
30
Sun May 06, 2007 11:16 am
f2001290 wrote:
For integers a and b, if sqrt(a^3 - a^2 - b) = 7, what is the value of a ?

1. a^2 - a = 12
2. b^2 - b = 2

Please explain the solution for this problem.
Using (1), you get a^2 -a - 12 = 0 which implies a = 4 or a = -3.
Hence insufficient.

Using (2), b^2 -b -2 = 0 which implies b = 2 or b = -1

a^3 - a^2 - b = 49
a^2(a-1) = 49 + b

We know a(a-1) should be even. so, b = -1

So, a^2(a-1) = 48

Only a=4 satisfies above eqn. sufficient.

Hence B

### Best Conversation Starters

1 lheiannie07 72 topics
2 LUANDATO 60 topics
3 ardz24 48 topics
4 AAPL 46 topics
5 M7MBA 45 topics
See More Top Beat The GMAT Members...

### Most Active Experts

1 Jeff@TargetTestPrep

Target Test Prep

141 posts
2 Brent@GMATPrepNow

GMAT Prep Now Teacher

136 posts
3 GMATGuruNY

The Princeton Review Teacher

134 posts
4 Rich.C@EMPOWERgma...

EMPOWERgmat

128 posts
5 Scott@TargetTestPrep

Target Test Prep

99 posts
See More Top Beat The GMAT Experts