Answer
10 degrees C.
Work Step by Step
Assume the amount of air (n) and the volume are both unchanged. Use the ideal gas law.
The value of P/T remains constant.
$$\frac{P_1}{T_1}=\frac{P_2}{T_2}$$
$$T_2=T_1\frac{P_2}{P_1}$$
$$T_2=(273+29K)\frac{191atm}{204atm}=283K\approx10^{\circ}C$$
