A box contains black and white marbles, the ratio of black marbles to white marbles is 3:5, and it is known that the total number of black and white marbles does not exceed 60. What is the maximum number of marbles in this box?
一个箱子中装了黑白两种弹子，黑弹子和白弹子的个数比是3：5，而且已知黑、白两种弹子的总数不超过60个．这个箱子中最多有弹子多少个？
<result>56</result>