Prime Numbers....

[evansbd]

If q is a multiple of prime numbers, is q a multiple of r?

1) r < 4.

2) q = 18.


I started writing out primes and their multiples however I wanted to know if anyone could share their insight with this question.

OA to follow...

[pranavc]

Is the OA C? PLease let me know.

[Stuart@KaplanGMAT]

If q is a multiple of prime numbers, is q a multiple of r?

1) r < 4.

2) q = 18.


I started writing out primes and their multiples however I wanted to know if anyone could share their insight with this question.

OA to follow...

Let's simplify:

"If q is a multiple of prime numbers" means "If q is an integer", since all integers are multiple of primes. (Technically, one could argue that q is a non-prime integer, but that would really be about semantics.) (Further, one could argue that this first piece of information is completely irrelevant, since we really only talk about integers when we discuss factors and multiples.)

So, the question really is:

"If q is an integer, is q a multiple of r?"

(1) r<4

Well, if q=25 and r=2, then no. If q=16 and r=2, then yes. Insufficient.

(2) q=18

No info about r, so insufficient.

Together:

Again, really depends how deeply we look at the question. Nowhere have we been told that r is a positive integer. So, if q=18 and r=1.2556121, then the answer would be "no". If q=18 and r=3, the answer would be "yes". Choose (e).

However, if we're supposed to assume (a dirty word in data sufficiency) that r is a positive integer, then r must be 1, 2 or 3, all of which give us a "yes" answer. Choose (c).

In conclusion, if this were a real GMAT question (something that's very unlikely, given the weirdness), the answer would be (e). If this is a question from a questionable source, the answer may "officially" be (c).

What's the source? Please post the source of all your questions so we can better evaluate how GMATesque the question really is.

[Ian Stewart]

"If q is a multiple of prime numbers" means "If q is an integer", since all integers are multiple of primes.

I agree that this is a bizarre question- it's either transcribed incorrectly, or it's simply terribly written. Still, a minor point, but the above is not quite correct. Even if we only consider positive integers, 1 is not a multiple of any prime. So if we know q is a positive integer (not something we're told, to be sure, but it's information you'd always find in a GMAT divisibility question), and we know 'q is a multiple of prime numbers', that means that q is an integer greater than 1. That doesn't affect the solution at all, however, and I can guarantee that you will never see a statement like 'q is a multiple of prime numbers' on the GMAT.

[evansbd]

https://www.4tests.com/exams/questions.asp?googlebot=31

Question # 16

This site gives a practice test, a very simple one, with some strangely worded questions sprinkled in like the one above.

The official answer is E.

I picked C like alot of posters.

[Stuart@KaplanGMAT]

https://www.4tests.com/exams/questions.asp?googlebot=31

Question # 16

This site gives a practice test, a very simple one, with some strangely worded questions sprinkled in like the one above.

The official answer is E.

I picked C like alot of posters.

Again, it's a crappy question, I wouldn't have much faith in anything from that source (but at least they got the answer right).