36kg of some material undergoes a process in a piston-cylinder apparatus starting with an initial volume of .057m^3 and pressure of 680kPa. The final volume is twice the initial. Compute the work done by the substance for the following processes: (a) Pressure times volume is constant

(Ans. 26.9kJ)

3 answers

Part of this question appears to be missing.
What do you think is missing? Given the initial volume and initial pressure plus the final volume and relationship between pressure and volume, I feel like you should be able to integrate pressure with respect to volume. I just cannot get the correct answer.
When I read the question it says "the following processes" but then (a) is a statement and not a process. We know PV = k