Speed = distance/time Which in your case means 50 meters/ 21.34 seconds, which equals 2.343 meters per second.
Helium if I was you I would have chooses helium haha
36.8%. divide 28.52 by 77.5 then multiply by 100
To subtract 7 from 102, you have to regroup. You subtract 2 from 100, and 2 from 7, so it is 100-5. 100-5 is 95. The answer is 95. If you don't understand, tell me in the comments. This is just one method of subtracting.
