z is jointly proportional to x^3 and y^2. If z=172 when x=6 and y=6, find z when x=4 and y=3

Question

z is jointly proportional to

x^{3}

and

y^{2}

. If z=172 when x=6 and y=6, find z when x=4 and y=3

Answer 1

z = k x^{3} y^{2}

If so, we plug in the original data to find k, then so from there thus we have

172 = k (6^{2}) (6^{3})

which given us
k=0.02212
Now we plug this in to the top equation and plug in the new x and y.

z = (0.02212) \cdot (4^{3}) \cdot (3^{2}) = 12.74

Answers (1)