Pls help me with this DS question

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Pls help me with this DS question

by mollyrg » Mon Jan 14, 2008 2:09 pm
Hello,
Pls help me with the following DS question:

Is xy<0 ?
(1) 1/x<1/y
(2) 0<x

Thanks,
Molly

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Re: Pls help me with this DS question

by preciousrain7 » Mon Jan 14, 2008 2:52 pm
mollyrg wrote:Hello,
Pls help me with the following DS question:

Is xy<0 ?
(1) 1/x<1/y
(2) 0<x

Thanks,
Molly[/quotes


Is the answer C?

If so, then my reasoning is as follows:

1. 1/x<1/y THIS TELLS YOU NOTHING ABOUT THE SIGNS OF X AND Y
2. 0<x THIS TELLS US THAT X is POSITIVE

If you combine statement 2 with statement 1, the positive fraction 1/x < 1/y, hence Y must be positive as well

if both X and Y are positive then XY can't be less than 0

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by cris » Mon Jan 14, 2008 3:49 pm
I also think it should be C.

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by cris » Mon Jan 14, 2008 3:50 pm
I also think it should be C.

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by doudou » Mon Jan 14, 2008 7:50 pm
I think it should be C also, because when you use each individual statement you cannot determin if xy > 0.

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by its_me07 » Wed Feb 06, 2008 9:20 am
i think it could b A

For xy<0 either x<0 or y<0
As 1/x <1> x>y
so if x>y then y must b less than 0.