Im studying for the Fundamentals of Engineering exam (coming up April 12!!) and came across this Thermodynamics problem in my review book. So the work for an isothermal process is RTA*ln(VB/VA), where VA was previously determined to be 0.103m3. In the solution to the problem, the RTA term is replaced with PA*VA, where it should be (PA*VA)/n from the ideal gas law. Is this solution wrong? As I see it, this cant be solved without knowing the number of moles of gas (or mass of the gas depending on which R is used). I was unable to get the correct answer, and the solution seems wrong to me.