BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

What is the value...?

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 51
Joined: Fri Apr 04, 2008 9:35 am

What is the value...?

by LMK27 » Sat Feb 13, 2010 8:24 pm
What is the easiest way to solve this?

If a + b = 9, what is the value of ab?

(1) a - b = 5

(2) b - a = -5


Statement (1) ALONE is sufficient, but statement (2) alone is insufficient.

Statement (2) ALONE is sufficient, but statement (1) is insufficient.

BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

EACH statement ALONE is sufficient.

Statements (1) and (2) TOGETHER are NOT sufficient.

Ans D
Top
Source: — Data Sufficiency |
User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pm
Thanked: 653 times
Followed by:252 members

by papgust » Sat Feb 13, 2010 8:56 pm
The easiest way is to just determine whether the equations could be solved simultaneously.

You have an equation with 2 unknowns in the question. To determine a and b, we need another equation to simultaneously determine a and b.

The 2nd equation with the same 2 unknowns are provided in Statement I and II. So, both are sufficient.

Remember. We just need to determine whether it's solvable in Data sufficiency questions. Here, we know that from 2 equations and 2 unknowns, we can determine the values of 2 unknowns. So, just knowing this itself is sufficient to answer.
Top
Post new topic Post Reply
• Page 1 of 1