One of Santa's elves can make one toy each minute. Every 2 minutes 1 toy falls apart. Every 5 minutes Santa takes 3 toys. If two elves are working in a room that contains 30 toys, than how many toys will there be after an hour, assuming that Santa has just left and that the elves work for the full hour?
Santa takes away 12 * 3 = 36 toys in the hour
Number of toys that the elves can make in one hour = 2 (60) =120
Number of toys that fall apart = 60 /2 = 30
So......number of toys starting out - ones that Santa takes - number that fall apart + number that elves make =
30 - 36 - 30 + 120 =
120 - 36 =
84 toys after one hour