Question

if Y varies jointly as X and the square of Z, and if Y=24 when X=2 and Z=6, find Y when X=10 and Z=9

Answer 1

y = kxz^2 , where k is a constan

given: y = 24, x=2, z=6

24 = k(2)(36)
k = 24/72 = 1/3

y = (1/3)xz^2
when x=10,z=9
y = (1/3)(10)(81) = 10/243

Answer 2

y varies jointly with z and the square of x. y=16 when z =2 and x=3, find y when z=3 and x=4