simple math

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awilhelm: Master | Next Rank: 500 Posts; Posts: 117; Joined: Fri Oct 17, 2008 7:41 am

by awilhelm » Tue Jan 20, 2009 2:57 pm

(1001^2 - 999^2) / (101^2 - 99^2)

a) 10
b) 20
c) 40
d) 80
e) 100

Fastest way to solve?

Source: Beat The GMAT — Problem Solving | Tue Jan 20, 2009 2:57 pm

Zipper: Master | Next Rank: 500 Posts; Posts: 119; Joined: Sun Nov 30, 2008 2:47 am; Thanked: 11 times

by Zipper » Tue Jan 20, 2009 4:36 pm

Just simplify it.

(1001-999).(1001+999)/(101-99).(101+99)=4000/400=10

awilhelm: Master | Next Rank: 500 Posts; Posts: 117; Joined: Fri Oct 17, 2008 7:41 am

by awilhelm » Tue Jan 20, 2009 6:27 pm

right, duh. Thanks.

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