DS-13

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DS-13

by desihokie » Fri Jan 18, 2008 12:09 am
powerprep Q
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by StarDust845 » Fri Jan 18, 2008 9:22 am

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by desihokie » Fri Jan 18, 2008 9:50 am
nope, the answer is C

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by StarDust845 » Fri Jan 18, 2008 10:23 am
Yup it's C. It's a shame.

From (1) we know x > y , so both could be +ve or -ve or whatever.

From (2) we don't know that x > y (this is the mistake I commited).
However, we do know that both x and y CAN be either +ve or -ve and |x| > |y|.

Combining both, x > y from (1). And 2 is impossible if we take -ve values for x and y in (2). Hence both must be positive.

All the best for your exam tomorrow by the way. Do let us know, how the test went and whether you encountered any probability problems, tricky problems etc.

Thanks,
Calista.