GMATBusters wrote:
Project DS Butler: Day 9: Data Sufficiency (DS18)
For DS butler Questions Click HereIs triangle MNP isosceles?
(1) Exactly two of the angles, M and N, have the same measure.
(2)Angles N and P do not have the same measure.
Target question: Is triangle MNP isosceles? Statement 1: Exactly two of the angles, M and N, have the same measure. Perfect. This is the precise definition of an isosceles triangle
The answer to the target question is
YES, triangle MNP is isoscelesSince we can answer the
target question with certainty, statement 1 is SUFFICIENT
Statement 2: Angles N and P do not have the same measureHere are two conflicting scenarios that satisfied statement 2
Case a: ∠N = 50°, ∠P = 80°, and ∠M = 50°. In this case, the answer to the target question is
YES, triangle MNP is isoscelesCase b: ∠N = 50°, ∠P = 70°, and ∠M = 60°. In this case, the answer to the target question is
NO, triangle MNP is not isoscelesSince we cannot answer the
target question with certainty, statement 2 is NOT SUFFICIENT
Answer: A
Cheers,
Brent
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Brent Hanneson – Creator of gmatprepnow.com
I’ve spent the last 20 years helping students overcome their difficulties with GMAT math, and the biggest thing I’ve learned is…
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