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Quantitative - DS

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by abhishekbansal » Wed Dec 10, 2008 12:48 am
x is a positive integer. Is ((1/2)^x) < 0.25?

1. x > 2
2. ((1/2)^(x - 1)) < 0.5

Pls help regarding the answer

As per me, the answer should be A

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Source: — Data Sufficiency |

by cramya » Wed Dec 10, 2008 5:29 am
It should be D) imo


Stmt II

1/2^x * 1/2 ^ -1 < .5

1/2 ^ x * 1/ (1/2)^1 < .5

1/2 ^ x * 2 < .5

1/2 ^ x < .25

which is what we need to find

SUFF
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by anayeri » Wed Dec 10, 2008 7:26 am
I'm with Cramya on this one, should be D.
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by ronniecoleman » Wed Dec 10, 2008 8:59 am
IMO D
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by NicoFalcon » Thu Dec 11, 2008 7:24 am
I´m too with D.

(1) is pretty obvious.
(2) For ((1/2)^(x - 1)) < 0.5 to be true, x should be >2.

Since with x=2, ((1/2)^(x - 1))=1/2 and it will start diminishing as x increases, x is AT LEAST 2 to accomplish with ((1/2)^(x - 1)) < 0.5
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