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# the statement is: Is r^5 > s^r

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Manager
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the statement is: Is r^5 > s^r [#permalink]

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03 Jan 2007, 23:26
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

the statement is: Is r^5 > s^r
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SVP
Joined: 01 May 2006
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04 Jan 2007, 01:48
(C) for me also

From (1)
o If r=s=1, then r^5 = s^r = 1
o If r=1 s=-1, then r^5=1 > (-1)^1 = -1

INSUFF.

From (2)

INSUFF.

(1) combined with (2)
r = s^4 = 16

We know r and s, so we can conlude.

SUFF.
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04 Jan 2007, 05:28
Taking logs on both sides

we need to find

5*logr > r*logs

logr/logs > r/5-----------(a)

but from (1) we have r = s^4

so substitute in (a)

4 > s^4/5

so 4> 16/5 (we know s=-2 from II)

so C
Manager
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04 Jan 2007, 07:29
You all got C, I had gotten C too, but the OA and OE is something else
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SVP
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04 Jan 2007, 07:58
jainan24 wrote:
You all got C, I had gotten C too, but the OA and OE is something else

And what about this case : If s=-1, then r=1 and r^5=1 > (-1)^1 = -1 ?

From what I read, it is explained that (-1)^((-1)^4) = 1.... that's not true ..... a^1 = a not |a|.

What is the source of this surprising question?
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04 Jan 2007, 12:07
jainan24 wrote:
McGrawhill GMAT

Thanks.

I have never heard about it before .... The OA & OE are wrong
Senior Manager
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04 Jan 2007, 15:24
You guys are right. ItÂ´s C.
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