Question

The quantity y varies directly as x and inversely as z. When x is 10 and z is 4, y is 15. What is y when x is 20 and z is 6?

Answer 1

Y=(kx)/z


15=(k10)/4
15=(5k/2)
15=k(5/2)
ties both sides by 2/5 to clear fraction
6=k

y=(6x)/z

x=20
z=6
y=(6*20)/6
y=20