tricky challenge question - Is CB || ED?
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- Brent@GMATPrepNow
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Is CB || ED?
(1) ∆ABC and ∆AED are both isosceles triangles
(2) ∠C = ∠E
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Statements combined:Brent@GMATPrepNow wrote:
Is CB || ED?
(1) ∆ABC and ∆AED are both isosceles triangles
(2) ∠C = ∠E
Case 1:
In this case, ∠B = ∠E and ∠C = ∠D, so CB || ED.
Case 2:
In this case, ∠B ≠∠E and ∠C ≠∠D, so CB ∦ ED.
Since the answer to the question stem is YES in Case 1 but NO in Case 2, INSUFFICIENT.
The correct answer is E.
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My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
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GMAT/MBA Expert
- Brent@GMATPrepNow
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Target question: Is CB || ED?Brent@GMATPrepNow wrote:
Is CB || ED?
(1) ∆ABC and ∆AED are both isosceles triangles
(2) ∠C = ∠E
Let's jump straight to....
Statements 1 and 2 combined
Statement 1 tells us that ∆ABC and ∆AED are both isosceles triangles
Statement 2 tells us that ∠C = ∠E
Let's start with 2 identical isosceles triangles:
If we arrange the triangles this way....
....we can see that the answer to the target question is YES, side CB IS parallel to side ED
HOWEVER, if we arrange the triangles this way....
....we can see that the answer to the target question is NO, side CB is NOT parallel to side ED
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT
Answer: E
Cheers,
Brent