Archimedes tells us the lifting power of a balloon (how much mass it can lift) is equal to the difference between the mass of the balloon and the mass of the air it displaces. That is, if the balloon occupies the same volume as of air, but the balloon only weighs 2kg, then the balloon can lift 8kg. Airships have sometimes been filled with hydrogen (H2), but hydrogen is very flammable, and after the Hindenburg caught fire and crashed in with serious loss of life airships have nearly always been filled with helium (He) instead. Suppose a new airship Star of Balogna will have the shape of a cylinder 40m long, with a radius of 4.0m , and will weigh 750kg without any gas inside it. Suppose also the average passenger weighs 80kg.

Required:
Calculate how many passengers the Balogna could carry if it were filled with hydrogen, and also if it were filled with helium.