First we are going to use boyle's law:
1- gas (N2) only : initially it is contained in Volume = 0.65 L .and finally it will spread out into V = 1.15 L when the initial pressure was 825 torr
the final pressure will be V1 * P1 = V2 * P2
0.65L x 825 torr = 1.15L x P2
So, P2 = 0.65L x 825 torr / 1.15L = 466.3 torr
∴ the partial pressure of N2 gas = 466.3 torr
2- then now O2 gas only: initially it is contained in V = 0.5L .and finally it will spread out into V = 1.15L when its initial pressure was 732 torr
so, the final pressure will be V1 * P1 = V2 * P2
0.5L x 732 torr = 1.15L x P2
∴ P2 = 0.5L x 732 torr / 1.15L = 318.3 torr
∴ the partial pressure of O2 gas = 318.3 torr.
3-The total pressure of both gases spread in the two bulbs is:
= the partial pressure of N2 + the partial pressure of O2
= 466.3 + 318.3 = 784.6 torr
∴ The total pressure is = 784.6 torr