1. The problem statement, all variables and given/known data 2. Relevant equations no 3. The attempt at a solution no Since the problem asks how much work was done by OR on the gas, I did not understand why the book's answer is 162 J instead ±81 J that I've found. (sorry my bad english) Sorry, the correct question on the problem is how much work was done from b to c instead from a to b as it's in the image.