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Bunuel
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TheNightKing
Anyone willing to post an alternate approach?

I got it right but not sure if that is the best approach.

I basically could not visualize the path to the solution.
GMATPrepNow may be you can help?

I can't think of an approach that's significantly different from the one lacktutor used.
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Quote:

I can't think of an approach that's significantly different from the one lacktutor used.

Thanks. I will solve using his approach and try to come up with mine.

Just one of those questions that bothers you :)
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I solved this differently

\(a^2b^2 + 5ab = 24 \)
\(\\
b^2 = 24 - 5ab / a^2\\
\\
\)

Looking at the options, I know that numerator must equal the answer so solved using the options

E) 24 - 5ab = 9, 5ab = 24 - 9, 5ab = 15

As this is divisible I choose this while the others didnt look divisible
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If a and b are not positive integer, if they are negative integer then answer will be B.
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b2 = (24 – 5ab)/a2

This implies that some multiple of 5 must be subtracted from 24.

Multiples of 5 which would leave a positive outcome are 5, 10, 15,20. Options A, B, C are eliminated since the numerator in these options is greater than 24 which is not possible given a and b are both positive.

Out of remaining two options only option e consistent with the given information.
24 - 5(3) = 24 – 15 = 9
Denominator is same for all the options. Hence, option e is the answer.
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