马克思曾经做过这样一道趣味数学题：有30个人在一家小饭馆里用餐，其中有男人、女人和小孩。每个男人花了3先令，每个女人花了2先令，每个小孩花了1先令，一共花去50先令。问男人、女人和小孩各有几人？-Marx have made such an interesting math problem: There are 30 people in a small restaurant meals, including men, women and children. It took three shill