Heat And Thermodynamics

A gas is expanded from an initial state to a final state along a path on a \(p\)-\(V\) diagram. The path consists of (i) an isothermal expansion of work 50 J , (ii) an adiabatic expansion and (iii) an isothermal expansion of work 20 J . If the internal energy of gas is changed by \(-\)30 J , then the work done by gas during adiabatic expansion is