GMAT Prep / Absolute Value
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- earth@work
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IMO : C
(1) x+y=z - insufficient, plugging values x=4,y=2,z=6,we get 4+2=6
absolute value(4)=4=6-2....correct,
but if we take x<0 ,say x=-4, y=2,z=-2,we get -4+2=-2
Absolute value of(-4) = 4 = -2-2=-4...incorrect
(2) gives us x<0, which is the case 2 of explanation above. this is not sufficient alone but sufficient when (1) &(2) are taken together.
(1) x+y=z - insufficient, plugging values x=4,y=2,z=6,we get 4+2=6
absolute value(4)=4=6-2....correct,
but if we take x<0 ,say x=-4, y=2,z=-2,we get -4+2=-2
Absolute value of(-4) = 4 = -2-2=-4...incorrect
(2) gives us x<0, which is the case 2 of explanation above. this is not sufficient alone but sufficient when (1) &(2) are taken together.
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Earth@work u r right about C) but may be not on the values picked
Stmt I
x=1 y=2 z=3
|X| = 1 but y-z = -1 so |x| <> y-z
INSUFF
Stmt II
x<0
x=-10 y=-100 z=-1000
|x| <> y-z
x=-1 y=2 z=1
|x| = y-z
INSUFF
Stmt I and II together
X+Y = Z
X<0
Take y negative(y>z) or positive(y>z) |x| = y-z
C)
Stmt I
|-4|= 4 y-z = 2-(-2) = 4 so |x| = y-zbut if we take x<0 ,say x=-4, y=2,z=-2,we get -4+2=-2
Absolute value of(-4) = 4 = -2-2=-4...incorrect
x=1 y=2 z=3
|X| = 1 but y-z = -1 so |x| <> y-z
INSUFF
Stmt II
x<0
x=-10 y=-100 z=-1000
|x| <> y-z
x=-1 y=2 z=1
|x| = y-z
INSUFF
Stmt I and II together
X+Y = Z
X<0
Take y negative(y>z) or positive(y>z) |x| = y-z
C)
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Folks,
I was thinking in entirely different way for this question..
Can anyone let me know the issue with my approach...
Question asked: Is |x| = Y - Z
this can be re-written as X = Y - Z and X = Z - Y or 2Z = 2Y
or Question asked can be re-written as is Z = Y?
From 1, we know that X + Y = Z ; we dont know the individual values...If X = 0, then Y = Z..if not, then Y != Z...So option A not sufficient..
From 2, we can derive nothing about Y and Z...
Combining both 1 and 2, since we know that X < 0, Y cannot be equal to Z...
So C is the answer.
I was thinking in entirely different way for this question..
Can anyone let me know the issue with my approach...
Question asked: Is |x| = Y - Z
this can be re-written as X = Y - Z and X = Z - Y or 2Z = 2Y
or Question asked can be re-written as is Z = Y?
From 1, we know that X + Y = Z ; we dont know the individual values...If X = 0, then Y = Z..if not, then Y != Z...So option A not sufficient..
From 2, we can derive nothing about Y and Z...
Combining both 1 and 2, since we know that X < 0, Y cannot be equal to Z...
So C is the answer.
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I am taking little different approach, would appreciate if anyone can let me know any issue with this approach ?
Question stem
Is |x| = y-z
==> we need to check
if y-z = +ve
From Statement 1
x+y = z ==> y - z = -x
thus y-z will be +ve if x is -ve hence insuff.
From Statement 2:
x<0 again insufficient
From 1 and 2 we get x<0
hence sufficient.
Question stem
Is |x| = y-z
==> we need to check
if y-z = +ve
From Statement 1
x+y = z ==> y - z = -x
thus y-z will be +ve if x is -ve hence insuff.
From Statement 2:
x<0 again insufficient
From 1 and 2 we get x<0
hence sufficient.