(1 / 2) the volume of the airship filled with hydrogen staying in the air is 3 * 10 cubic meters, the density of air is 1.29kg/cubic meter, and the density of hydrogen is 0 (1 / 2) the volume of the airship filled with hydrogen staying in the air is 3 * 10 cubic meters, the density of air is 1.29kg/cubic meter, the density of hydrogen is 0.09kg/cubic meter, and the weight of the airship is 1.29kg/cubic meter

(1 / 2) the volume of the airship filled with hydrogen staying in the air is 3 * 10 cubic meters, the density of air is 1.29kg/cubic meter, and the density of hydrogen is 0 (1 / 2) the volume of the airship filled with hydrogen staying in the air is 3 * 10 cubic meters, the density of air is 1.29kg/cubic meter, the density of hydrogen is 0.09kg/cubic meter, and the weight of the airship is 1.29kg/cubic meter

Buoyancy of airship f = ρ air * g * V airship = 1.29 * 10 * 3 * 10 ^ 3 = 3.87 * 10 ^ 4 n
Because the airship stays in the air, gravity = buoyancy
So the total weight of airship plus hydrogen plus cargo = 3.87 * 10 ^ 4 n
Weight of goods = 3.87 * 10 ^ 4-300-0.09 * 10 * 3 * 10 ^ 3 = 3.6 * 10 ^ 4 n