If 9 is a factor of 2z, then which of the following may not be an integer? Choose the correct choice
A) 6z/54 + 2z/3 B) (4z-18)/9 C) (2z+27)/9 D) (81-4z^2)/81 E) (2z-3)/3
I got the right answer A after plugging in 18 for z.   While going through Kaplan's explanation, I couldn't understand the part about choice A.   "6z/54 + 2z/3 = 3/6 * 2z/9 + 2z/3.   Since 9 is a factor of 2z, 3 is also factor of 2z. So 2z/3 is an integer, as is 2z/9. But 3/6 = 1/2, so if 2z/9 is not even, the expression 3/6 * 2z/9 will not be even."   But, isn't 2z/9 always even? 9 is a factor of 2z, 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 2z/9 is even.6z/54 + 2z/3
<result>A</result>
If 9 is a factor of 2z, then which of the following may not be an integer?