Data Sufficiency

A and B are positive integers. Is A a factor of 24?
1.AB is a factor of 24
2. B=4

Answer is D !!

I would say C. Any answer?

I wouldn't agree with D as factors are not the same as multiples. (crosses fingers)

imo E

I think answer should be 'a'

Answer is A

X is a Factor of Y is y/x = integer.

from a) we know, 24/(a*b) = integer , so 24/a = integer*b = integer.

Hence A is a factor of 24

Answer is indeed A.

Here is how you can find the difference between factors and multiples
if there are 3 numbers x, y & z such that x*y = z
then x and y both are factors of z and z is a multiple of xy.
Factors are also known as Divisors.

Statement I
AB is the factor of 24, then A must be a factor of 24.
Sufficient.

Statement II
B=4
no idea about A.
Insufficient.

Hence A is the answer.

Thank you guys for you responses, Sumit's strategy also works well in this question, which infact is the same rule as above.

Just curious - where is this question from?

sumithshah wrote:Just curious - where is this question from?

This question is from one of the tests on LearnHUb.com Thought this question would be interesting to clear up on factors, multiples and divisors. I guess it did help lot of people considering the responses.

Learn Hub stuff any good?

Also you've got your gmat tomorrow rt? good luck onit