For this question, we will be using Boyle's gas Law, which is a law that shows the relationship between volume and pressure of a gas with constant temperature, the formula is:
P1V1 = P2V2
We have:
P1 = 16.7 kPa
V1 = 46.5 L
P2 = 9.1 kPa
V2 = ?
Now we add these values into the formula:
16.7 * 46.5 = 9.1 * V2
776.55 = 9.1V2
V2 = 85.3 L is the new volume