Question

Suppose that y varies jointly with w and x and inversely with z and y = 175 when w = 5, x = 20 and z = 4. Write the equation that models the relationship. Then find y when w = 2, x = 24 and z = 6.

Answer 1

A]Given that y varies jointly with w and x and inversely with z and y = 175 when w = 5, x = 20 and z = 4.
then
y=kwx/z
where k is the constant or proportionality given by:
k=yz/wx
but
y=175, when w=5, x=20, z=4
hence
k=(175*4)/(5*20)
k=7
Thus the equation is:
y=(7xw)/z

b]find y when w = 2, x = 24 and z = 6.
y=(7*2*24)/6
y=336/6
y=56