The work for the process in Btu

Carbon dioxide gas within a piston-cylinder assembly undergoes a process from an initial state of 5 psia, and 2.5 ft3 to a state of 20 psia, and 0.5 ft3. The path taken is indicated by the relationship P = 24 — 8V, where V is in ft3 and P is in psia. Determine the work for the process, in Btu. (Hint: Watch "Work Calculation")