What is the Greatest Common Divisior of two different positive integers which are less than 144 ?
(A) 143
(B) 142
(C) 72
(D) 71
(E) 12
(A) 143
(B) 142
(C) 72
(D) 71
(E) 12
The answer is D. If we are looking at common divisor of two numbers less than 144, both the numbers cannot be prime numbers and hence atleast one of them has to be divisible by factor other than 1 and the number. Now applying POE on each choice:beat_gmat_09 wrote:What is the Greatest Common Divisior of two different positive integers which are less than 144 ?
(A) 143
(B) 142
(C) 72
(D) 71
(E) 12
A - Wrong. If this is the greatest divisor than the other number has to be multiple of it, which is not possible as the number has to be less than 144
B - Wrong. The reason same as for the reason for choice A
C - Wrong. The reason same as for the reason for choice A
D - Right. The numbers can be 72 and 142
E - There are other numbers greater than 12 (like choice D)
