If a < x < b and c < y < d, is x < y ?

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by Brent@GMATPrepNow » Thu Nov 30, 2017 10:32 am
VJesus12 wrote:If a < x < b and c < y < d, is x < y ?

(1) a < c
(2) b < c
Target question: Is x < y?

Given: a < x < b and c < y < d

Statement 1: a < c
This statement doesn't FEEL sufficient, so I'll TEST some values.
There are several scenarios that satisfy statement 1 (AND the given information). Here are two:
Case a: a = 1, x = 2, b = 3, c = 4, y = 5 and d = 6. In this case, x < y
Case b: a = 1, x = 10, b = 11, c = 4, y = 5 and d = 6. In this case, x > y
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: b < c
Perfect, this information allows us to COMBINE the two given inequalities.
We get: a < x < b < c < y < d
At this point, it is clear that x < y
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: B

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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