Suppose y is jointly proportional to x and z. What is y when x=2 and z=3, if y=20 when z=4 and z=3?
y = k * x * z
20 = (k) * (4) * ( 3)
20 = 12k
k = 20/12 = 5/3
y = (5/3) (2) ( 3)
y = 10
