HMMT 二月 2000 · POW 赛 · 第 5 题
HMMT February 2000 — POW Round — Problem 5
题目详情
- Assume that nob o dy has a birthda y on F ebruary 29th. Ho w large m ust a group b e so that there is a greater than 50% han e that at least 2 mem b ers ha v e the same birthda y?
解析
- W e w an t 1 365 364 363 : : : (365 n + 1) = 365 > 50%. Just guestimating giv es the answ er of 23 p eople.