Question 62970
Given that w varies directly as x and inversely as the square of y.

So w can be written as w = K *x/(y^2) where k is the constant of proportionality.

when x = 15, y = 5, w = 36

Plugging in these value,  

36 = K*[15/(5^2)]
==> 36 = K*(15/25)

Multiplying both the sides by 25/15 we get,

36*(25/15) = K
==> 36*(5/3) = K
==> 60 = K

Thus the constant of proportionality is 60.

The equation becomes,
W = 60x/(y^2)


Good Luck!!!