GMAT Data Sufficiency (DS) | Re: |a-b|=? 1) |a+b|=10 2) |a^2-b^2|=20

==> In the original condition, there are 2 variables (a,b) and in order to match the number of variables to the number of equations, there must be 2 equations. Since there is 1 for con 1) and 1 for con 2), C is most likely to be the answer. By solving con 1) and con 2), you get |a^2-b^2|=|a+b||a-b|=20, 10|a-b|=20, |a-b|=2.

The answer is C.
Answer: C

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