Find the volume of the composite space figure to the nearest whole number

If y varies directly as x2 and y=6 when x=6, find the constant of variation.

If 30 lb of rice and 30 lb of potatoes cost ? $27.60? , and 20 lb of rice and 12 lb of potatoes cost ? $15.04? , how much will 10 lb of rice and 50 lb of potatoes? cost?

Can someone, me with this. i really need with this