let's assume that the number of women is 5x, then the number of children and the number of men should be 2x and 4.4x respectively. You need to keep that every number must be an integer in mind, which means 4.4x and 2x all should be integers. Meanwhile, 5x<30, then x <6, then x can only be 5 to satisfy the precondition that 4.4x is an integer.
不知道LZ看的明白不，也算我练习一下英文。。。设女人有5x只，小孩有2x只，则男人有4.4x只。不可能出现什么22.1个人这种数字，所以4.4x必须是整数。5x<30，那么x<6，实际上只有x=5的时候才能满足4.4x是整数。
