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

Redeem

GMATprep PS question

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 39
Joined: Sun Jun 15, 2008 10:50 pm
Thanked: 4 times

by Motherjane » Sat Jun 28, 2008 2:28 pm
(sqrt 2 + sqrt 5) ^ 2 is of the form (a+b)^2 = a^2 + b^2 + 2 ab

or, 2 + 5 + 2( sqrt 2 * sqrt 5) = 7 + 2( sqrt 10)

sqrt 10 > sqrt 9 which is 3

so approximately the value will be : 7 + 2(3) = 13
Top
Master | Next Rank: 500 Posts
Posts: 151
Joined: Fri Jun 13, 2008 7:31 am
Thanked: 1 times

by mlane25269 » Sat Jun 28, 2008 9:17 pm
Thanks for the explanation, MotherJane!

Is (a+b)^2 = a^2 + b^2 + 2 ab some kind of formula used for square root problems like this because I haven't seen it in any of the GMAT books I've read.
Top
Post new topic Post Reply
• Page 1 of 1