Yvaries jointly with w and x, inversely with z, and suppose y=360 when w =8,x=15, and z =3. write the equation that models this relationship

Y varies jointly with w and x, inversely with z
this means that
y ∝ wx / z
in equation form
y = kwx / z
where k is the proportionality constant
360 = k ( 8 ) ( 15 ) / 3
k = (360) ( 3) / ( 8 ) ( 15 )
k = 9
so the eqution is
y = 9wx / z