Mathematics`s questions?!?

Question

The attractive force (F) between two objects varies directly as the product of their masses (M1 and M2) and inversely as the square of their distance (d) . If M1 and M2 are both halved and d is doubled , find the ratio of the new value of F to its original value .

Answer 1

F2 = (M1/2)*(M2/2)/(2d)^2 = (M1)*(M2)/(16*d^2) = F1/16.