Four people eat instant-boiled mutton. According to a box of 500g mutton slices, at least five boxes of mutton slices need to be purchased. Moreover, the quantity to be purchased depends on everyone's food intake, and also depends on whether the thickness of mutton is enough. If it is a very thin slice of mutton, the quantity purchased will increase. After that, it depends on whether you only eat instant-boiled mutton and whether you will add other ingredients, which will also affect the amount of mutton you finally buy. Moreover, if four people are divided into men and women, their food intake will increase and decrease. Men generally don't eat very little. If they are all men, you'd better buy about ten boxes. The cost of buying mutton alone is estimated to be about eighty or ninety yuan.