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ds -ve integer

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ds -ve integer

by advita » Thu Jan 20, 2011 5:54 am
If m and n are negative integers, what is the value of (mn)?
(1) m^n = 1/81
(2) n^m =-(1/64)


i doubt for B...Oa is B..

pl explain your choice.
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by jaxis » Thu Jan 20, 2011 6:42 am
N^M = -(1/64)

N=-4
M=-3

or

N=-64
M=-1

B cant be the OA.


It shud be C
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by aleph777 » Thu Jan 20, 2011 8:19 am
The clue to the answer here is that the original question states that both M and N are negative numbers. Therefore, right of the bat, we know that negative * negative = positive, but positive * negative = negative.

Statement 1 is INSUF because you can reach 1/81 two ways:
-9^-2 (which is negative * negative) OR -3^-4 (which is negative * negative * negative * negative)

Statement 2 is SUF because there's only one combination that will yield a -(1/64):
-8^-2 = 1/64 BUT -4^3 = -(1/64)
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by AIM GMAT » Thu Jan 20, 2011 8:36 am
Wow !! Thanks aleph777 and jaxis as well as advita for this question , i also went with C .Now i know where i was mistaken . Silly makes me go crazy .... i will keep this in mind .
Thanks & Regards,
AIM GMAT
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by advita » Thu Jan 20, 2011 7:53 pm
hi guys... thanks all.
but i still doubt how it is B.

Q:If m and n are negative integers, what is the value of (mn)?
(1) m^n = 1/81
(2) n^m =-(1/64)

as jaxis told:
2. consider n=-4 m=-3 so n^m=-1/64. ==> mn=12
if n= -64, m= -1, so n^m=-1/64 ==> mn=64.

so how it can be B.
1. m=-9,n=-2 or m=-3 , n=-4


so isn't it should be E.

pl confirm. thanks.
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by aleph777 » Fri Jan 21, 2011 6:49 am
ohhhhh... i see what you're saying. that is weird. i'm not sure, then. it would seem you'd need to pick C after all.
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by samrendra4u » Fri Jan 21, 2011 8:00 am
advita wrote:If m and n are negative integers, what is the value of (mn)?
(1) m^n = 1/81
(2) n^m =-(1/64)


i doubt for B...Oa is B..

pl explain your choice.

It should be B.
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by advita » Fri Jan 21, 2011 10:35 am
yeah it should be C...!!!
thanks guys.
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