A cylinder fitted with a frictionless piston contains 0.2 kg of saturated (both liquid and vapor present)

Question:

A cylinder fitted with a frictionless piston contains 0.2 kg of saturated (both liquid and vapor present) R-12 at -20oC. The external force on the piston is such that the pressure inside the cylinder is related to the volume by the expression:
P = - 47.5 + 4.0 x V1.5, kPa and L
Heat is now transferred to the cylinder until the pressure inside reaches 250 kPa.
Calculate the work and heat transfer.