Suppose A is directly proportional to B, B is inversely proportional to C and C is inversely proportional to D. Determine whether A and D are directly proportional, inversely proportional, or neither.

Answer 1

C is inversely proportional to D ---> C = p/D
B is inversely proportional to C ---> B = qC
so B = q/(p/D) = (q/p)D

A is directly proportional to B --> A = rB
A = r(q/p) D
looks like A is directly proportional to D