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

Redeem

If a square with 20 as one side’s length and decreases to

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 am
Location: Las Vegas, USA
Thanked: 19 times
Followed by:37 members

If a square with 20 as one side’s length and decreases to

by Max@Math Revolution » Mon Mar 21, 2016 5:30 pm
Image

If a square with 20 as one side's length and decreases to a and b shown as above figure, what is the area of the region shaded?

1) (a+b)^2=49
2) (a^2)+(b^2)=25


* A solution will be posted in two days.
Top
Source: — Data Sufficiency |
User avatar
Elite Legendary Member
Posts: 3991
Joined: Fri Jul 24, 2015 2:28 am
Location: Las Vegas, USA
Thanked: 19 times
Followed by:37 members

by Max@Math Revolution » Thu Mar 24, 2016 3:55 pm
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

If a square with 20 as one side's length and decreases to a and b shown as above figure, what is the area of the region shaded?

1) (a+b)^2=49
2) (a^2)+(b^2)=25


When you modify the original condition and the question, 20^2-(a^2/2)-(b^2/2)=400-(a^2+b^2)/2 is derived, which makes 2) sufficient.
Thus, B is the answer.
Top
Post new topic Post Reply
• Page 1 of 1