If 9 is a factor of 2a, then which of the following may not be an integer? Select
A) 6a/54 + 2a/3	B) (4a-18)/9	C) (2a+27)/9	D) (81-4a^2)/81	E) (2a-3)/3
I got the right answer A after plugging in 18 for a.   While going through Kaplan's explanation, I couldn't understand the part about choice A.   "6a/54 + 2a/3 = 3/6 * 2a/9 + 2a/3.   Since 9 is a factor of 2a, 3 is also factor of 2a. So 2a/3 is an integer, as is 2a/9. But 3/6 = 1/2, so if 2a/9 is not even, the expression 3/6 * 2a/9 will not be even."   But, isn't 2a/9 always even? 9 is a factor of 2a, which means that we could have 2(9), 2(2)(9), 2(3)(9), and so forth. The 9 in the denominator cancels out the 9 in the numerator. So we are left with 2 * something. So 2a/9 is even.6a/54 + 2a/3
<result>A</result>
If 9 is a factor of 2a, then which of the following may not be an integer?