GMAC PREP PROBLEM

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GMAC PREP PROBLEM

by sangeethmani » Tue Dec 15, 2009 2:08 pm
This is silly may be but i am confused..
In Isosceles triangle RST what is the measure of R?
(1) the measure of T is 100
(2) the measure of S is 40

I want to know without the condition given that which of the two sides are equal how can u say what it measures , unless u have both the the statements.
The correct answer is B
Source: — Data Sufficiency |

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by papgust » Tue Dec 15, 2009 8:59 pm
Why isn't the answer A here?

A triangle cannot be more than 180 degrees. You know that RST is an isosceles triangle and T as 100 degrees.
As T is 100, R and S should have the same angle and R can be found.

With S as 40 in statement 2, you don't know whether R or T has the same angle as S. Please clarify.