题目网址: http://www.puzzleup.com/2016/
http://www.puzzleup.com/2016/puzzle/?16
答题时限: 11月10日7PM-比赛结束(约12月14日)
加分时限: 11月10日7PM-11月16日6:59PM
答对可得基本分100分。答案可上传5次,每改1次答案从基本分扣20分。
比赛期间内可随时上传答案,加分时限内答对第n天加(6-n)分
另依题目的难易有额外加分(如有80%的人这题答错,答对者加80分)
◆FIVE NUMBERS
Five numbers are selected randomly between 1 and 100 (1, 2, ..., 99, 100). If
the selected numbers are all different and their sum is equal to 100, the
smallest number is noted. If this process is repeated many times, what would
be the average of the noted numbers?
Note: All numbers have the same probability of selection.
Enter your answer as a simplified fraction. Example:12/23
由 1 至 100 中均匀随机选取五个数。
若此五数互不相同且其总和恰为 100, 则记下此中最小的数字。
重复此操作许多次后,所记下数字的平均为何?
以最简分数回答,如 12/23。