[s3a]

I do not understand how to do the following question:

The valve connecting a 2.00L bulb containing N2 at 530 torr and a 3.00L  bulb containing O2 at 195 torr is opened. After equilibration, what is the total pressure, in atm, in the system? Assume the temperature remains constant.

Answer: 0.433 atm

Any help would be greatly appreciated!
Thanks in advance!