The gas laws (Boyle/Charles) states that P1*V1/T1=P2*V2/T2, where P, V and T are pressure, volume and degrees Kelvin. Put P1=1 atm, V=100ml and T=230°K. Put P2=1.5 atm, T2=200°K, need to find V2. So 1.5V2/200=100/230, so V2=200/1.5*100/230=4000/69=57.97ml. This is a mathematical physical problem based on proportions. Pressure is inversely proportionate to volume (more pressure reduces gas volume) and directly proportional to absolute temperature (the higher the pressure the greater the temperature, e.g., in a bicycle pump the temperature of the pressurised air in the pump rises as the pump compresses the air, as you can find out painfully by putting your finger over the end that would normally be attached to the wheel!).
