Agas is contained in a 5.0-liter container at a pressure of 100 kpa. what size container would be required to contain the gas at a pressure of 50 kpa, assuming the temperature remains constant? a). a 2.5-liter container b). a 7.5-liter container c). a 10.0-liter container d). a 15.0 liter container

Boyle's law gives the relationship between pressure of a gas and volume of gas.
It states that at constant temperature, pressure of gas is inversely proportional to volume of gas.PV = k 
where P - pressure  V- volume and k - constant 
P1V1 = P2V2 
since the gas occupies the volume of the container, volume of gas is taken as volume of container.
100kPa x 5.0 L = 50 kPa x V
V = 10.0 L 
Answer is C.