1. The problem statement, all variables and given/known data A balloon is to be filled with helium(density = 0.178kg/m^3) while the air outside has density of 1.29km/m^3. The mass of the empty balloon is 80.0kg and it is to lift a load of 240kg. What minimum volume is necessary for the lift off? Assume that the balloon material and the load occupy negligible volumes. 2. Relevant equations density = M/V 3. The attempt at a solution I'm not quite sure how to start with this question. Can someone help me please?