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by gmataug08 » Sat Nov 29, 2008 9:55 am
IF xy + z = x(y+z), which of the following must be true?

a) x= 0 and z= 0
b) x= 1 and y =1
c) y= 1 and z = 0
d) x= 1 or y=0
e) x= 1 or z=0

OA : e

what is wrong with option a?
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by cramya » Sat Nov 29, 2008 11:21 am
Its been solved before. Cant find the link

xy + z = x(y+z),

xy+z = xy+xz

xz-z=0
z(x-1) = 0

z=0 or x=1 must be true.

Choice E)
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by gmataug08 » Sat Nov 29, 2008 8:08 pm
I understand why the option E is right, but even option A does satisfy the basic equation isn't it?
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by eracnos » Sat Nov 29, 2008 8:22 pm
which of the following must be true?
We can have z=0 and x = 1,2,3,4,5,6,7,8 ...... so A is wrong
Feeling blue is feeling true
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by gmataug08 » Sat Nov 29, 2008 8:34 pm
eracnos wrote:
which of the following must be true?
We can have z=0 and x = 1,2,3,4,5,6,7,8 ...... so A is wrong
ok, I get it, in option A, z must be 0 but x need not be zero,so A is wrong.
(I guess this answers why my verbal score is so low :( )
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