If Z is directly proportional to the square of X and inversely proportional to the cube of Y, how is Z affected when both X and Y are increased by 50%

Question

This question is under the topic direct and inverse proportion

Answer 1

Z = kX²/y³ = Z₁

 

If x and y are increased by 50%, then:

 

   Z₂ = k(1.5x)²/(1.5y)³

 

        = kx²/[1.5y³] = (2/3)Z₁

 

So, if x and y are both increased by 50%, then Z decreases by 1/3  (33.333%).