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Is x^3 equal to 125 ?

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Source: — Data Sufficiency |

Re: Is x^3 equal to 125 ?

by Brent@GMATPrepNow » Tue Mar 02, 2021 9:38 am
BTGModeratorVI wrote:
Tue Feb 16, 2021 8:13 am
Is x^3 equal to 125 ?

(1) x > 4
(2) x < 6

Answer: E
Source: Princeton Review
Target question: Is x^3 equal to 125 ?

REPHRASED target question: Does x = 5?

When I scan the two statements, they both feel insufficient, AND I’m pretty sure I can identify some cases with conflicting answers to the target question. So, I’m going to head straight to……

Statements 1 and 2 combined
Statement 1 tells us that x > 4
Statement 2 tells us that x < 6
Combine to get: 4 < x < 6
Since we're not told x is an INTEGER, there are infinitely man y values of x that satisfy BOTH statements. Here are two:
Case a: x = 5. In this case, the answer to the REPHRASED target question is YES, x is equal to 5
Case b: x = 5.1. In this case, the answer to the REPHRASED target question is NO, x is not equal to 5
Since we can’t answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer: E

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
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