If x / y is an integer, which of the following statements must be true?
A. both x and y are integers.
B. x is an integer.
C. either x or y is negative.
D. y / x is an integer.
E. x = ny where n is an integer.
You can eliminate answer choices by selecting numbers.
For example, in option A, x and y could both be equal fractions and x/y would be an integer.
For the same reason option B does not have to be correct.
There is no reason for either of them to be negative.
Option D does not need to be correct. Consider x/y = 6/3. Then y/x = 3/6, which is a fraction not an integer.
But rearranging x/y = n, we get x = ny which is therefore always true.