posted by Anonymous .
The air inside a hot air balloon has an average temperature of 71.7° C. The outside air has a temperature of 11.1° C. What is the ratio of the density of air in the balloon to the density of air in the surrounding atmosphere?
Since the pressure is very nearly the same inside and outside the balloon, density is inversely proportional to absolute temperature.
rho_inside/rho_outside = T_outside/T_inside
= 284.3/344.9 = 0.824