Answer
Radius of the Balloon = 12.5 m
the skin and the cargo of the balloon have a mass = 850 kg
Volume of balloon=[tex]\dfrac{4}{3}\pi r^3[/tex]
=[tex]\dfrac{4}{3}\ \pi\times 12.5^3[/tex]
=8181.20 m³
Mass the ballon can carry= volume x [density of air-density of helium]
=8181.2 x [ 1.29 - 0.179 ]
=9089 kg
Mass of cargo = 9089 - 850
= 8239 kg
