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DS

by sophia_qur@hotmail.com » Thu Dec 11, 2008 10:51 am
Is rst = 1 ?
(1) rs = 1
(2) st = 1

E

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by cramya » Thu Dec 11, 2008 10:56 am
Stmt I and Ii by itself is insufficient

Stmt I no info about t

Stmt II no info about r

Together

rs = 1
st = 1

rs * st = 1*1

rs^2t = 1

All three r,s and t could be 1

or

r=1 s=1/2 t=4

rs^2t = 1 but rst <> 1

E)

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Re: DS

by parallel_chase » Thu Dec 11, 2008 11:40 am
sophia_qur@hotmail.com wrote:Is rst = 1 ?
(1) rs = 1
(2) st = 1

E
Cramya's solution is perfect, here is another way

Statement I & II insufficient without a doubt

Combining I & II

rs = 1
st = 1

r=1, s=1, t=1

rst = 1--------yes

r=-1, s=-1, t=-1

rst = -1-------no

Insufficient.

Hence E. I love to hate fractions :)
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by ronniecoleman » Thu Dec 11, 2008 11:06 pm
YUP

IMO E


rs = 1
st =1

now from one rs =1 but nothing abut t so OUT

now from second st =1 nothing about r so OUT

Now from both

rsst = 1
s*s = 1/ rt

rst = 1/s

we don't know about s

so OUT
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