If a, b, and c are positive numbers, is a < b < c
(1) ab = bc
(2) ac = bc
OA:D Explain.
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If a, b, and c are positive numbers, is a < b < c
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vinodhinir
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Stat. 1....vinodhinir wrote:If a, b, and c are positive numbers, is a < b < c
(1) ab = bc
(2) ac = bc
OA:D Explain.
Since ab = bc, by cancelling b, we get a = c => It means a is not less than c.Ans is No.
Sufficient condn.
Stat. 2....
Since ac = bc, by cancelling c, we get a = b => It means a is not less than b.Ans is No.
Sufficient condn.
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GMATGuruNY
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Statement 1: ab = bcvinodhinir wrote:If a, b, and c are positive numbers, is a < b < c
(1) ab = bc
(2) ac = bc
OA:D Explain.
Since b>0, we can divide by b.
The result: a=c.
Thus, it is not true that a<c.
SUFFICIENT.
Statement 2: ac = bc
Since c>0, we can divide by c.
The result: a=b.
Thus, it is not true that a<b.
SUFFICIENT.
The correct answer is D.
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vinodhinir
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it is not true that a<c.
but how can we conclude that a is not less than b
lets say if b is 3 and a is 2 then a<b ...
if it s the other way round then a > b
how can this be a sufficient condn ?
I know am missing something very trivial here,but cannot think of what could it be ...
but how can we conclude that a is not less than b
lets say if b is 3 and a is 2 then a<b ...
if it s the other way round then a > b
how can this be a sufficient condn ?
I know am missing something very trivial here,but cannot think of what could it be ...
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GMATGuruNY
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The information in statement 1 (a=c) renders the value of b irrelevant.vinodhinir wrote:it is not true that a<c.
but how can we conclude that a is not less than b
lets say if b is 3 and a is 2 then a<b ...
if it s the other way round then a > b
how can this be a sufficient condn ?
I know am missing something very trivial here,but cannot think of what could it be ...
Since a=c, it is not possible that a<b<c.
SUFFICIENT.
There are only 3 possible scenarios:
If a=c and a<b, then c<b. Thus, a<b<c is not true.
If a=c and a=b, then a=b=c. Thus, a<b<c is not true.
If a=c and a>b, then c>b. Thus, a<b<c is not true.
In each case, it is not true that a<b<c.
SUFFICIENT.
Similar reasoning can be applied to statement 2.
Last edited by GMATGuruNY on Mon Apr 16, 2012 5:55 am, edited 1 time in total.
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Birottam Dutta
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You have to understand that if you can prove any of a<b, a<c or b<c false, then it is sufficient to answer the question.
Remember in DS, the answer need not always be a correct one, even if the statements can prove the question to be incorrect, even that is considered as a sufficient statement.
Remember in DS, the answer need not always be a correct one, even if the statements can prove the question to be incorrect, even that is considered as a sufficient statement.
Folks please check this out
https://www.youtube.com/watch?v=H7p56NzAVKc
https://www.youtube.com/watch?v=H7p56NzAVKc
