For the air-inflow crap which I didn't fully understand:
47: C
48: D
49: C
Anyone who understood the question want to confirm it? 
I got
47: C
48: C
49: D
here's my reasoning, but I'm not 100% sure of it
For 48
Look at Figure 1, if you are pushing in and P and Q are both closed, then the air can't go into Room 1, so it must be forced up, and if you have R open and S closed, the air will go through R and back up the inlet, since it can't go through S.
Figure 2 is pretty the same as figure 1, but with everything reversed. Therefore, by similarity, you would need T and U closed, S open and R closed.
So summing it all up, P, Q, R, S, T and U must be reversed from what they are in the digrams.
For 49
The only way air can get to room 1 is if it goes through R so it can be pushed through P and Q. The only other option, going through S is no good because the Rubber Seal prevents the air from ever getting past and going into Room 1.