1、on a certain sight-seeing tour, the ratio of the number of women to the number of children was 5 to 2, what was the number of men on the sight-seeing tour?
(1) on the sight-seeing tour, the ratio of the number of children to the number of men on the tour was 5to 11.
(2)The number of women on the sight-seeing tour was less than 30.
PREP 给的答案是C， 但是我觉这道题算不出来啊，第二个条件只给了women less than 30， 没有具体数值啊？所以men的number算不出来啊……
serenashu的签名
You make millions of decisions that mean nothing and then one day your order takes out and it changes your life.作者: avalon9527 时间: 2011-2-11 17:24
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。作者: 小宇宙2010 时间: 2011-2-11 21:09
