so he got them for £10 all 24 bars, then he went and sold each for 50c, so hmmm 24 at £0.50 that's (24)(0.5) = 12, so he bought them for £10 and sold them for £12, he's got a surplus or profit of £2.
now, if we take 10(origin amount) as the 100%, what's 2 off of it in percentage?
