If you want to solve for the volume of a gas (V2) and P1 is greater than P2, would you expect V2 to be larger or smaller than V1?
The relevant gas law is Boyle's Law:
For a fixed mass of gas at constant temperature the pressure of the gas is inversely proportional to its volume.
So if the volume of the gas is increased the gas pressure will decrease.
We can also write the relationship above as
In the case of this question