Could you help me to solve this please and just explain the procedure...

1. An utomobile tire is inflated to 32 psig pressure at 50 degrees Farenheit. After driven the temperature rise to 75 farenheit. Determine the final gage pressure assuming the volume is constant. Answer: 34.29 psig

2. If 100 ft^3 of atmospheric air at zero Farenheit temperature are compressed to a volume of 1 ft^3 at a temperature of 200 deg Farenheit, what will be the pressure of the air in psi? Answer:2109 psia

Thanks a lot...