If x, y, and z are positive integers such that x is divisible by y, and y is divisible by z, which of the following is NOT necessarily an integer?
Pick.
A) xy/z	B) (x + y)/z	C) xz/y	D) (x - y)/z	E) (x + z)/y
As per the question, let x = 12, y = 6, and z = 2. Plugging these into the answer choices, only E does not yield an integer. The reason is that (x + z)/y = x/y + z/y, and while x/y must be an integer, z/y is only an integer if y = z.
<result>E</result>
If x, y, and z are positive integers such that x is divisible by y, and y is divisible by z, which of the following is NOT necessarily an integer?