is a – b + c greater than a + b – c ?

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If a,b, and c are integers, is a - b + c greater than a + b - c ?
(1) b is negative.
(2) c is positive.


stem: is a-b+c > a+b-c
is a+2c>a+2b ?

from 1 & 2.. we can say that a+2c is always greater than a+2b.. (for both a as +ve and -ve) hence Answer is C


is the above approach right ?

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by harsh.champ » Sun Feb 21, 2010 5:41 pm
Nijeesh wrote:If a,b, and c are integers, is a - b + c greater than a + b - c ?
(1) b is negative.
(2) c is positive.


stem: is a-b+c > a+b-c
is a+2c>a+2b ?

from 1 & 2.. we can say that a+2c is always greater than a+2b.. (for both a as +ve and -ve) hence Answer is C


is the above approach right ?
Yes,your approach is perfectly fine.
a-b+c > a+b-c
This implies that a+2c>a+2b

Now, b<0
and c>0
Hence,c>b
So,both statements together are sufficient.C.
Hence,your answer holds.
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by shashank.ism » Sun Feb 21, 2010 5:53 pm
Nijeesh wrote:If a,b, and c are integers, is a - b + c greater than a + b - c ?
(1) b is negative.
(2) c is positive.


stem: is a-b+c > a+b-c
is a+2c>a+2b ?

from 1 & 2.. we can say that a+2c is always greater than a+2b.. (for both a as +ve and -ve) hence Answer is C


is the above approach right ?
to check: a-b+c > a+b-c --> -b+c>b-c
St.1) b is negative , b<0 -->not suff we don't sign of a and c
St.2) c is positive. c>0 --> not suff we don't know sign of a and b

combined ) b<0 and c>0 so -b+c > b-c hence suff.Ans C
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by lunarpower » Tue Feb 23, 2010 6:49 am
why aren't you guys simplifying the question all the way?

viz.:
IS a - b + c > a + b - c ?
cancel the a's:
is -b + c > b - c ?
add b to both sides, AND add c to both sides:
is 2c > 2b?
divide by 2:

Is c > b ?

this is the simplified question.

what's ... interesting is that TWO posters did HALF-simplifications (one of you got to "-b+c>b-c" and the other to "a+2c>a+2b", but neither of those posters went all the way to the simplified version)

with this question, it's much easier to see that the answer is (c).
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by hamxa » Thu Mar 11, 2010 9:29 am
RON: The maker of this question will be mortified if he sees the way u have cut it open (he better not ... :) )