So today I did my friend's homework, and that was to solve mathematical things in movies. Friend chose Up, and here I went with doing not my homework. Spoiler: Number of Balloons needed to lift up a house Let’s assume the house you’re trying to lift weighs 35 tonnes. 1ML of Helium can lift 1 tonne Therefore, you’ll need around 35 ML (35,000,000 L) of Helium to lift a house of this weight. Let’s assume each balloon is spherical, and they all had a diameter of 25 cm (radius of 12.5 cm). You can get the formula for the volume of a sphere using (4/3)*pi*r^3 (4/3) 3.14 12.5 ^ 3 = about 8177 cm^3. Let’s round this to 8200cm^3. 1000 cm^3 = 1 Litre, so a balloon would hold 8.2 litres of helium. 35,000,000 / 8.2 = about 4268293 So you would need a MINIMUM of 4268293 helium balloons to lift up a 35 tonne house. Spoiler: Price of everything minus the house Helium is worth about $25/L, so that’d make the total helium worth around $875,000,000 ($875 million) _____ On Amazon.com, 144 balloons costs $6. (http://www.amazon.com/Assorted-Colo...=UTF8&qid=1449554483&sr=8-2&keywords=balloons) 4268293 (total number of balloons) * $6 / 144 (number of balloons) = $177845.54 ______ Let’s assume each balloon is paired with 1000 inches of string to go along with it, that’d be about 28 yards. 28 (yards) * 4268293 (balloons) = 119512204 total yards 500 yards of string = $5 (http://www.amazon.com/Berwick-Splen..._21_img_2?ie=UTF8&refRID=16JHWBFGMZK7ZKNGKSTA) 119512204 (total yards) / 500 (yards per spool) * $5 = $1,195,122.04 _____ Now add all the prices up 875,000,000 + 177,845.54 + 1,195,122.04 = $876,372,967.58 ARE YOU PROUD OF ME SYKIKAL

Nice job on this, it's just normally with math problems they tend reference numbers from the book or some source material so there's no variance. What if the price of string on amazon went up or down by the time you made this or different students found different sites to buy string on? Maybe I should be surprised at that other teachers are lazy by comparison and wouldn't let a variable like this slip in and would rather just grade with only 1 correct answer, but that just seems to be the norm with math related stuff.