Tough DS question. Can anyone explain this?

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Source: — Data Sufficiency |

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by bha » Tue Aug 26, 2008 12:11 pm
are u sure about the question?..
I think stmt 2 should be x^3>x^2....for 'C' to be answer...

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by madsport » Tue Aug 26, 2008 12:21 pm
Thanks bha! I made the correction right away. The actual question states x^3 < x^2. I initally thought the question creators stated the expression incorrectly, but wanted the Beatthegmat community to take a crack at it before dismissing the problem

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madsport wrote:What is the value of x?

1) x^4 = 625
2) x^3 < x^2


The answer is C (Data Sufficiency)
It actually makes no difference which way the inequality points in statement (2) - in either case, the answer would be (C).

(1) is insufficient because we don't know if x is positive or negative.
(2) is insufficient because we have no clue what the actual value of x is, there are many possibilities.

Together, however, we can narrow it down to just 1 value.

From (1), we know that x = +/- 5

If x^3 < x^2, we know that x can no longer be +5, so it must be -5.

If x^3 > x^2, we know that x can no longer be -5, so it must be +5.

Either way, we get one exact value: together the statements are sufficient, choose (C).
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