A 2.34L container of H2(g)at 752mmHg and 24 degrees is connected to a 3.17L container of He(g) at 717mmHg and 24 degrees.

After mixing, what is the total gas pressure, in millimeters of mercury, with the temperature remaining at 24 degrees?

I would use PV = nRT to determine the mols H2 gas in the 2.34 L container and use it again to determine the mols He gas in the 3.17 L container. Add the mols together and use PV = nRT to determine the total pressure from the total mols. There may be an easier way to do it but this is easier to explain, at least to me. A word of caution, P is in atm so you will need to convert the mm Hg given to you initially for each gas (mm Hg/760 = atm), so through the equations outlined above, find the final P in atm, then convert back to mm. Post your work if you get stuck.