There is a 100 square meter hot air balloon, still in the air, with air density of 1.29 kg / m3 and buoyancy of a.12

There is a 100 square meter hot air balloon, still in the air, with air density of 1.29 kg / m3 and buoyancy of a.12

F floating = ρ gas GV exhaust = 1.29 kg / m3 × 9.8 N / kg × 100 m3 = 1264.2 n
If ρ = 10 N / kg, the answer is 1290 n