Help Needed !!

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Help Needed !!

by Soumita Ghosh » Sat Feb 09, 2013 7:10 pm
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I chose A

Please let me know whether I am correct?

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by Ian Stewart » Sun Feb 10, 2013 3:17 am
The question asks:

Is 10^(-x) < 0.01 ?

We can rewrite the question so we have powers of 10 on both sides:

Is 10^(-x) < 1/100 ?
Is 10^(-x) < 10^(-2)

and for the answer to be yes, the power on the left side needs to be smaller than the power on the right side, so our question becomes

Is -x < -2 ?
Is x > 2?

So Statement 2 is not sufficient, but only on a silly technicality that you would never see on the real GMAT - Statement 2 leaves open the possibility that x is exactly equal to 2.

The typesetting in Statement 1 is a bit bizarre but I think it means to say:

10^(-x) + (6/25) < 1/4

which we can rewrite:

10^(-x) < 1/4 - 6/25
10^(-x) < 25/100 - 24/100
10^(-x) < 1/100

which is precisely what we wanted to prove. So Statement 1 is sufficient and the answer is A.
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