If y varies inversely as x and y=3 when x=4 then y=12 when x=15 true or false

In the first case, x*y = 4*3 = 12

In the second case, x*y = 15*12 = 180

The results 12 and 180 don't match, so the answer is false

Side Note: if x and y vary inversely with one another, then x*y = k for some fixed number k

Inverse proportion is x=k/y, where k is the constant. So let's find the value of k:

4=k/3

4*3=k

k=12

Now substitute x for the second situation into the equation:

15=12/y

12/15=0.8

y=0.8, so the given answer is false