Is |x| = y - z ?
(1) x + y = z
This tells us that y - z = - x
We know that |x| = x if x > 0 and |x| = - x if x < 0
Thus |x| = y - z if and only if x is less than or equal to 0
However, we don't know the sign of x. NOT SUFF
(2) NOT SUFF
(T) SUFF
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GMAT Prep Question help needed : Tomo is my exam
Source: Beat The GMAT — Problem Solving |
Hi,
From(1): x=z-y. So, |x| = |z-y| = z-y, if x>=0 and y-z if x<=0
Insufficient
From(2): x<0, we know nothing about the relation between x,y,z
Insufficient
Combining (1) & (2)
|x| = y-z
Sufficient
Hence, C
From(1): x=z-y. So, |x| = |z-y| = z-y, if x>=0 and y-z if x<=0
Insufficient
From(2): x<0, we know nothing about the relation between x,y,z
Insufficient
Combining (1) & (2)
|x| = y-z
Sufficient
Hence, C
Last edited by Frankenstein on Wed Jun 01, 2011 4:09 am, edited 1 time in total.
Cheers!
Things are not what they appear to be... nor are they otherwise
Things are not what they appear to be... nor are they otherwise
|x|=y-z?
a)x+y=z => y-z=-x = |x| only when x<0
insufficient
b)x<0
nothing about y and z. insufficient.
a&b) x<0 thus l.h.s. = -x = y-z
true
IMO C
a)x+y=z => y-z=-x = |x| only when x<0
insufficient
b)x<0
nothing about y and z. insufficient.
a&b) x<0 thus l.h.s. = -x = y-z
true
IMO C













