The greatest common factor of 16 and the positive integer n is 4, and the greatest common factor of n and 45 is 3. Which of the following could be the greatest common factor of n and 840?  Choose the correct answer
A) 15	B) 48	C) 64	D) 84	E) 105
n includes the factors 2^2 (but not 2^3) and 3 (but not 3^2 or 5)   840 = 8*3*5*7   The GCF could be 12 or 84.   The answer is 84.
<result>D</result>
The greatest common factor of 16 and the positive integer n is 4, and the greatest common factor of n and 45 is 3. Which of the following could be the greatest common factor of n and 840?