The school canteen sells roasted cold noodles to earn money. According to the relevant public information, it can be known that a roast cold noodle in the school cafeteria is about 5- 10 yuan, and the cost is only 1.5-2.5. The minimum profit of each roast cold noodle is four yuan, and the profit margin is still relatively large, so the school cafeteria sells roast cold noodles to earn money.