* If X & Y are positive integers such that x=8y+12

[a123]

If X & Y are positive integers such that x=8y+12,
What's the greatest common divisor of X & Y

1. X = 12u (u = integer)

2. Y = 12u (u = integer)

Answer is B.

I'm confused as both (1) and (2) give you 3,2,2 as prime factors for the GCD. Why is (2) sufficient but (1) not?

Is it because Y is already divisible by 8 (shown by 8Y)?

Thanks

[RonPurewal]

please search the forum before you post; there are lots and lots and lots of threads on this problem.

here's the longest:
in-x-and-y-are-positive-integers-such-that-x-8y-12-t902.html

if you have any further questions after reading that thread, please post them there, not here.
thanks.

this thread is now locked, and will be deleted shortly.