Jerry bought 48 firecrackers for the 4th of July. A police officer discovered and confiscated 12 of them. 1/6 of the remaining ones were defective. If Jerry set off half the good firecrackers, how many firecrackers did he set off? Think carefully first, then make a decision:
First subtract the 12 confiscated firecrackers from the original number: 48 firecrackers - 12 firecrackers = 36 firecrackers. Then multiply this number by 1 / 6 to find how many were defective: 36 firecrackers * 1 / 6 = 6 firecrackers. Then subtract the defective firecrackers to find how many were good: 36 firecrackers - 6 firecrackers = 30 firecrackers. Then divide this number in half to find how many firecrackers Jerry set off: 30 firecrackers / 2 = 15 firecrackers. So, the answer is 15.