Yvaries jointly as x and z. y=72 when x=6 and z=4. find y when x=3 and z=6.

This is a Joint variation problem which is solved using the equation y = k*x*z.

Solve for "k" using y=72 when x=6 and z=4.
72 = k*6*4
k = 3

Now put k back into the original equation of y= k*x*z and solve.

y = 3*3*6

y = 54

The correct answer is addition

Set up a system of equations