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DS Question please help

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DS Question please help

by moonlite » Thu Sep 04, 2008 4:52 pm
Is m not equal to n?

1) m + n < 0
2) mn < 0

OA is B

The explanation given is that since mn is negative one of the two numbers must be negative and the other positive.

BUT

can't we say that .5 x .5 = 0.25 which is also less than 0?
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Source: — Data Sufficiency |
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Re: DS Question please help

by parallel_chase » Thu Sep 04, 2008 5:12 pm
moonlite wrote:Is m not equal to n?

1) m + n < 0
2) mn < 0

OA is B

The explanation given is that since mn is negative one of the two numbers must be negative and the other positive.

BUT

can't we say that .5 x .5 = 0.25 which is also less than 0?
0.25 is greater than 0

Therefore statement B is sufficient as one number has to positive and one number has to be negative.

Hope this helps. Let me know if you have any doubts.
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confused - data sufficiency...

by acerche » Thu Nov 06, 2008 1:31 pm
why isn't the answer D.

because looking at 1....

m+n < 0
therefore m < -n sufficient

or

n < -m sufficient

i.e. m does not equal n

am I missing something??
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by jaybrium » Thu Nov 06, 2008 1:46 pm
The answer is B- try not to overthink this one.

I) m + n < 0

m = -2
n = -1

-2 + -1 = -3 < 0; m is not equal to n

m = -2
n = -2

-2 + -2 = -4 < 0; m is equal to n; two answers are possible, insufficent

acerche, notice that m < -n and n < -m holds true in both these situations.

II) see Parellel Chase's explanation.

B :-)
- Jay
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