If 7 and 9 are factors of 60n, what is the minimum value of n?  Choices
A) 2 B) 3 C) 7 D) 14 E) 21
60n/7*9 should be integer =&gt; 2*2*3*5*n/7*3*3 = 2*2*5*n/21 must be an integer   for this to be true n must multiple of 21, thus min of n = 21   hence 21
<result>E</result>
If 7 and 9 are factors of 60n, what is the minimum value of n?