A balloon has a volume of 1000 m3 and a mass of 500 kg when empty. When full of helium, what is the maximum mass it can lift off the ground? The density of helium is 0.18 kg/m3 and the density of air is 1.29kg/m3.

Answer 1

Mass of helium=0.18x1000=180kg
Mass of displaced air=1.29x1000=1290kg
Net difference=1290-180=1180kg=total mass it can lift.
Net payload=1180-500=680kg

Answer 2

It says that the correct answer is 610 kg. How did they get 610 kg as the answer?

Answer 3

It was a typo. :)

Net difference=1290-180=1110kg=total mass it can lift.
Net payload=1110-500=610kg