Came across this problem which I cannot figure out in Jeppesen Sanderson PHYSICS FOR AVIATION.

Here it goes:

"The air pressure and density at a point on the wing of a B 747 flying at an altitude of 2900 m are 71.0 kPa, and 0.919 kg/m^3 respectively. What is the temperature at this point on the wing in degrees Centigrade?"

I would very much appreciate the process taken to figure this problem out shown for understanding. Thank you all very much for your help!

Paul