最新提问
我的动态
登录后查看动态
题目内容双击单词支持查询和收藏哦～
40 DVDs (17 are about psychology, 14 are about biology, and 9 are about history) need to be arranged in a bookshelf such that the 9 history-related DVDs are, on the whole, arranged in chronological order. How many ways can these DVDs be arranged?
D显示答案
以上解析由 考满分老师提供。
