Question

I need an answer to the analogy

fifteen:five::nine: ?

Answer 1

fifteen divided by five is three.
To complete the analogy, divide nine by three. (Your answer is three)

Answer 2

If the "analogy" is to preserve ratios on both sides, then the answer is 3. If the analogy is to preserve the difference, the answer is -1.

This is not a good way to teach fifth grade math, or analogies, in my opinion. The problem would be better stated as
15/5 = 9/x