题目网址: http://www.puzzleup.com/2018/
http://www.puzzleup.com/2018/puzzle/?7
答题时限: ９月13日７ＰＭ－比赛结束（约12月12日）
加分时限: ９月13日７ＰＭ－９月19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）　　
◆DICE GAME
You will play a game with a fair 6-sided die. You will throw the die and
as long as the result of the throw is greater than or equal to the previous
throw, you will continue throwing. If the throw is lower than the previous
one, you will stop and get as many points as the sum of all throws,
including the last one. For example, if you get 2, 5, 5, and 3 as a result
of 4 throws, the game will end with 15 points.
What is the expected value of the points you will get at the end of the game?
Enter your answer as a reduced fraction. Example: 123/4567
你要玩一个使用公平六面骰的游戏。一直丢骰子，只要这次丢出来的点数大于或等于上
次丢出来的点数，就可以一直丢下去。如果点数比之前的小，那么游戏结束，你的分数
为所有掷出的点数和，包括最后一掷。举例来说，你丢了2,5,5,3，总共丢了四次，游
戏结束得分为15。
试问游戏结束时，你得分的期望值为何？
以最简分数回答，如 123/4567。