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jimmytwoshoes
- Junior | Next Rank: 30 Posts
- Posts: 10
- Joined: Fri Jul 25, 2008 5:12 pm
Definitely by using the difference of squares:
(1001^2 - 999^2)/(101^2 - 99^2)
= [(1001 + 999)(1001 - 999)]/[(101+99)(101-99)]
=(2000*2)/(200*2)
=10
I can guarantee that you will see a difference of squares on your real GMAT- I just can't tell you where you'll see it. It may be in an algebra problem, but it can also appear in geometry, number theory, even percent increase and decrease- in almost any subject area. Be sure you can recognize it when it shows up.
