Sixty-eight people are sitting in 20 cars and each car contains at most 4 people.What is the maximum

题目

Sixty-eight people are sitting in 20 cars and each car contains at most 4 people.What is the maximum possible number of cars that could contain exactly 1 of the 68 people?
我的解题步骤是:
设x个人一个人一辆车,Y个人4个人一辆车.
x+y=68
x+y/4=20
二元一次方程的答案是固定的啊.X=4,Y=64
……………………………………………………
可是题目为什么要问maximum X 是不是我理解错了呢?

答案

Y个人4个人一辆车
这个假设有待商榷.
因为也可以是3人一辆车,2个人一辆车.但这样,一个人一辆车的答案就会小于4.
你设其他的车都是4人的,已经是为了求出maximum possible number 了.你的过程是对的,答案也是对的.
能明白我的解释么.