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 60?  Choose one
A) 3	B) 30	C) 40	D) 42	E) 70
Greatest common factor n and 16 is 4 = 2*2 * 2*2   Greatest common factor n and 45 is 3 = 3*3 *5   Greatest common factor n and 60 is = 2*3*5= 
<gadget id="calculator">2*3*5</gadget>
<output>30</output>
30   Answer: 30.
<result>B</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 60?