What pressure must be used to compress 850 ml of argon gas at 146 kpa to 150 ml? (temperature is held constant.)

Boyle's law states the relationship between pressure and volume of a gas. 
At constant temperature, pressure of a gas is inversely proportional to its volume.
PV = k 
P - pressure, V - volume and k - constant 
P1V1 = P2V2
parameters for the 1st instance are on the left side and parameters for the 2nd instance are on the right side 
146 kPa x 850 mL = P2 x 150 mL 
P2 = 827.33 kPa

They can measure  the amount of energy gained or lost