Hey, can someone please help me with this problem. Thanks a lot.

Question: A 1.00 L container of He at 300. torr is connected by a small valve to a 2.00-L container of Ne at 200. torr, which is also connected by a small valve to a 3.00-L container of argon at 100. torr. Calculate the partial pressure (torr) of each gas and the final pressure (torr) in the system after the valves connecting the gases are opened and the system thoroughly mixes.

What I did: P(He)= 300. torr
P (Ne)= 200. torr/2 = 100 torr
P (Ar) = 100. torr/3 = 31.33 torr.
adding all the torr and then dividing by 6 = 52.21 torr. but all of these answers are incorrect. Can someone tell me what to do or what I did wrong. Thanks again!!!!!!!