I can't find solutions to these two and desperately need help :

20. An ideal diatomic gas is initially at temperature T and volume V. The gas is taken through three reversible processes in the following cycle: adiabatic expansion to the volume 2V, constant volume process to the temperature T, isothermal compression to the original volume V. For the complete cycle described above, which of the following is true?

(A) Net thermal energy is transferred from the gas to the surroundings.

(B) The net work done by the gas on the surroundings is positive.

(C) The net work done by the gas on the surroundings is zero.

(D) The internal energy of the gas increases.

(E) The internal energy of the gas decreases.

24. A counter near a long-lived radioactive source measures an average of 100 counts per minute. The probability that more than 110 counts will be recorded in a given one-minute interval is most nearly

(A) zero (B) 0.001 (C) 0.025 (D) 0.15 (E) 0.5