# A truck gets 600/x miles per gallon when driven at a constant speed of x mph, where 40 < x <  80. If the price of fuel is $2.80/ gal and the driver is paid$12/hr, at what speed is it most economical for the trucker to drive?

Question

A truck gets 600/x miles per gallon when driven at a constant speed of x mph, where 40 < 80. If the price of fuel is $2.80/ gal and the driver is paid$12/hr, at what speed is it most economical for the trucker to drive?