PUMaC 2016 · 组合（B 组） · 第 1 题
PUMaC 2016 — Combinatorics (Division B) — Problem 1
题目详情
- Two fair six-sided dice are rolled. The probability that the positive difference between the two m rolls is at least 4 can be written in simplest form as . Compute m + n . n
解析
- The possibilities for the rolls of the dice are (1 , 5), (1 , 6), (2 , 6), (5 , 1), (6 , 1), and (6 , 2), so the 6 1 probability is = . Thus, the answer is 1 + 6 = 7 . 36 6 Problem written by Eric Neyman.