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## Divisble by 5

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dipzzz Just gettin' started!
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Divisble by 5 Sun May 06, 2012 8:26 am
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• Lap #[LAPCOUNT] ([LAPTIME])
x is a positive number. If 9^x + 9^x+1 + 9^x+2 + 9^x+3 + 9^x+4 + 9^x+5 = y, is y divisible by 5?
1) 5 is a factor of x.
2) x is an integer.

isn't the question stem sufficient??

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Bill@VeritasPrep GMAT Instructor
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Sun May 06, 2012 9:27 am
We need to know that x is an integer. If x is a decimal, then we could end up with decimal values for our terms, i.e. 9^2.2=~125.7

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klmehta03 Rising GMAT Star
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Sun May 06, 2012 12:53 pm
IMO A .
OA pls?

dipzzz Just gettin' started!
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Sun May 06, 2012 9:33 pm
OA D

bryan88 Really wants to Beat The GMAT!
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Fri May 11, 2012 10:15 pm
Dont we get 9^(x) *66430 on expansion.

This is anyway divisible by 5.

Am i missing something?

lathmanu Just gettin' started!
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Sat May 12, 2012 1:48 am
bryan88 wrote:
Dont we get 9^(x) *66430 on expansion.

This is anyway divisible by 5.

Am i missing something?
Yes the Question can be written as 66430*(9^x)

I would refer to Bill's reply.
We need to know that x is an integer.

Bill@VeritasPrep wrote:
We need to know that x is an integer. If x is a decimal, then we could end up with decimal values for our terms, i.e. 9^2.2=~125.7
I first took B as the answer.
But after seeing the original answer as D, I realized that if 5 is a factor of x, then x is an integer.
A is also sufficient.

Thanks for the question dipzzz

ihatemaths Really wants to Beat The GMAT!
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Sat May 12, 2012 6:30 am
how do you people get 66430 ? did you compute fully ?

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