Answer
1000 degrees C.
Work Step by Step
Use the ideal gas model. The amount of air, n, is constant. The value of PV/T remains constant.
$$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$$
$$T_2=T_1\frac{P_2}{P_1}\frac{V_2}{V_1}$$
$$T_2=(293K)\frac{40atm}{1atm}\frac{1}{9}=1302K\approx1000^{\circ}C$$