We can solve this problem using the pressure- volume relationship of gases, illustrated by Boyle's law:
We can see that pressure and volume for gases are inversely proportional, indicating that as one increases, the other must decrease (assuming constant temperature). Since the volume decreased, we can expect an increase in the pressure of the gas.
To keep calculations consistent, let's convert the units
Now that we have our necessary variables, let's rearrange the Boyle's law equation to solve for the final pressure,
Now, plugging in known variables, we have
The units for pressure above,
Thus, the pressure can also be reported as
If you want another unit of pressure, a more common one when dealing with gases, we can convert this to atmospheres using the conversion factor