Answer:
A
Step-by-step explanation:
Nonlinear would be any function where both values are not changing by some fixed amount. In B, f(x) increases by 1 for every time x increases by 1 so that's linear. For C, f(x) increases by 2 for every time x increases by 1, so that's linear. For D, f(x) increases by 3 for every time x increases by 1 so that's also linear. For A, f(x) does not always change by the same amount, so it's nonlinear.
20/15=N/27
Do cross multiplication.
20x27=540
540/15=39
So the answer ia 39.
I think it's 330 I don't really know