Hint 6-61

An Ideal Gas equation + Daltons Law problem.
There are several ways to solve this.

You can calculate the partial pressures for each of the gases
converting from the first volume condition (eg 2L)
to the second volume condition (eg 7L).
Then you sum the partial pressures – Daltons Law.

Or - you can first work out the total number of moles you are dealing with
and then you calculate the pressure with the new volume.