balloon filled with exactly 1 sq ft of helium yields about 28.2g (upward thrust)
453.6 grams/Lb
453.6(1Lb) /28.2= about 16 blns
So to get one pound off of the ground it would take about 16 balloons
16x200= 3200
it would take 3200 balloons to lift a 200 lb person....Only hoover not continually rise on account of the uneven weight distribution and the temp differences in each balloon helium isn't as buoyant when cold, unless the temp is consistant. Wind is a factor; as well as the amount of static charge in the air