问答题A typist types four envelopes and four letters. She places the letters in the envelopes at random. What are the chances that only three letters are in their correct envelopes?

题目
问答题
A typist types four envelopes and four letters. She places the letters in the envelopes at random. What are the chances that only three letters are in their correct envelopes?
更多“问答题A typist types four envelopes and four letters. She places the letters in the envelopes at random. What are the chances that only three letters are in their correct envelopes?”相关问题