There are red and white balls in a box, the total number does not exceed 60, and the ratio of red balls to white balls is 4:5, what is the maximum number of balls in this box.
一个盒子中有红、白两种球，总数不超过60个，其中红球和白球个数的比是4：5，这个盒子中最多有多少个球．
<result>54</result>