Boy Meets Girl

來源: 於 2010-04-13 18:10:10 [舊帖] [給我悄悄話] 本文已被閱讀：次
A boy and a girl agree to meet in the park. Each will show up at a random time between 12:00 and 13:00, and wait for the other person 20 minutes, but not past 13:00.

What is the probability that they will actually meet?