A reversible engine contains 0.350 mol of ideal monatomic gas, initially at 586 K and confined to

Question:

A reversible engine contains 0.350 mol of ideal monatomic gas, initially at 586 K and confined to a volume of 2.42 L. The gas undergoes the following cycle:
⋅ Isothermal expansion to 4.64 L
⋅ Constant-volume cooling to 282 K
⋅ Isothermal compression to 2.42 L
⋅ Constant-volume heating back to 586 K
Determine the engine's efficiency in percents, defined as the ratio of the work done to the heat absorbed during the cycle.