A Hot Air Balloon Along with Its Cargo Has a Mass

Multiple Choice

A hot air balloon along with its cargo has a mass of 4.0 x 10⁵ kg, and it holds 7.0 x 10⁵ m³ of hot air. It is floating at a constant height in air with a density of 1.29 kg/m³. What is the density of the hot air in the balloon?

A) 1.4 kg/m³
B) 0.72 kg/m³
C) 0.57 kg/m³
D) 0.86 kg/m³
E) 0.43 kg/m³