What is the greatest common divisor of positive integers m and n?

(1) m is a prime number.

(2) m and n are consecutive integers.

Hi All,

This DS question can be solved by TESTing VALUES and/or a bit of logic.

We're told that M and N are both POSITIVE INTEGERS. We're asked for the greatest common divisor of M and N.

1) M is a prime number.

This Fact tells us nothing about N.

IF...
M = 2
N = 2
Then the answer to the question is 2

IF...
M = 2
N = 3
Then the answer to the question is 1
Fact 1 is INSUFFICIENT

2) M and N are CONSECUTIVE integers.

The second TEST from Fact 1 'fits' this Fact too...

IF...
M = 2
N = 3
Then the answer to the question is 1

Looking at this example, you might notice that when dealing with consecutive positive integers, the ONLY factor that will divide into both numbers is 1. If you 'TEST' 3 and 4, 4 and 5, 5 and 6, etc., you 'll get the SAME answer every time.
Fact 2 is SUFFICIENT

Final Answer:

GMAT assassins aren't born, they're made,
Rich
_________________

Using the rule that any two consecutive are co- primes we can say B is sufficient and GCD =1
hence B
_________________

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________