Need HELP on Interpreting DS question

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Need HELP on Interpreting DS question

by BlindVision » Sat Mar 28, 2009 2:35 pm
If ab = 8, is a greater than b?

1) -3b GREATER THAN/EQUAL -18

2) 2b GREATER THAN/EQUAL 8


OA = B

I originally thought the answer was E because the question ask "is a greater than b", not if "b is greater than a"; I can see the answer being B if it was asking "is b greater than a".

Can someone help me interpret this question or trap? I think the wording is tricky.

Should I gather that if I'm presented with this kind of question form, to go with a Statement that can either prove or disprove the question, rather than looking for the Statement that proves the question?
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by cramya » Sat Mar 28, 2009 3:32 pm
If u know b is greater than a then u can easily tell if a is greater than b or not which is the question.

From stmt II u know b>= 4 so defnitely a is not greater than b

SUFF


Whenever any statement leads to a definite yes or a definite no in yes/no questions then that statement becomes SUFFICIENT to answer the question.

Hope this helps!

Regards,
CR

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by BlindVision » Sat Mar 28, 2009 3:58 pm
cramya wrote: Whenever any statement leads to a definite yes or a definite no in yes/no questions then that statement becomes SUFFICIENT to answer the question.
I definitely learned something new today about DS question-wording! I'm glad to have stumbled across this question and "Thank you" Cramya [as always] for the interpretation/insight.
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by gmat740 » Sat Mar 28, 2009 6:11 pm
Mathematical Interpretation:

1) -3b>= -18

so b<=6

Now b can have value, lets say from 6 to1

if b= 6, a<b
and if b=1 a>b[ because a=8 when b=1]

So insuff

Now

2) 2b>= 8
b>=4
So min value of b is fixed to be 4 and it can increase from 4 onwards
So the max value a can have is 2 and when value of B increases, value of a will further decrease from 2

in all cases, a<b

so Suff

So B