A farmer is selling watermelons in the market.The first time
A farmer is selling watermelons in the market.The first time he sells half of the watermelons and a half watermelons.The second time he sells half of the rest and a half watermelons.The third time he sells half of the rest and a half watermelons.The last time he sells half of the rest and a half watermelons.Now he has one watermelon.How many watermelon does he have at first?