Question

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

Answer 1

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

Answer 2

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