[tex]\rho = \frac{m}{V} \Rightarrow m=\rho V[/tex]
ρ - density, m - mass, V - volume
[tex]V=2850 \ m^3 \\
\rho=0.1685 \ \frac{kg}{m^3} \\ \\
m=2850 \ m^3 \times 0.1685 \ \frac{kg}{m^3} =480.225 \ kg \approx 480 \ kg[/tex]
The balloon contains approximately 480 kg of helium.
