It takes 6 yuan to process a kilo of corn by a corn bulking machine. Although it takes a short time to bulking a kilo of corn, it will take at least ten minutes. In fact, 6 yuan's labor cost is not too much, because one 12 horsepower diesel engine is used for processing, and the machine, diesel and mechanical wear cost consumed in one hour is as little as ten yuan, so it takes ten minutes to expand a catty of corn, and the mechanical cost is about 7 yuan. Two people operate on the machine, and the labor cost is about two yuan. Therefore, the mechanic can only earn a little more than two yuan for expanding a catty of corn, and maybe he can earn some money if the expansion quantity is more.