There are 9 kg, 6 kg, and 2 kg of sugar and 15 kg, 8 kg, and 7 kg of flour in each bag. The price of each kg of flour is half the price of each kg of sugar. Someone buys 5 bag, and he spent the same amount of money in buying sugar as in buying flour, so how many kilograms of that bag of food did he not buy.
有9千克、6千克、2千克的糖和15千克、8千克、7千克的面粉各一袋，每千克面粉的价钱是每千克糖的价钱的一半，某人买这六袋食品中的5袋，并且他买糖用去的钱和买面粉用去的钱一样多，那么，他多少千克的那一袋食品没有买．
<result>2</result>