HMMT 二月 2000 · 代数 · 第 6 题
HMMT February 2000 — Algebra — Problem 6
题目详情
- Barbara, Edw ard, Abhina v, and Alex to ok turns writing this test. W orking alone, they ould nish it in 10, 9, 11, and 12 da ys, resp e tiv ely . If only one p erson w orks on the test p er da y , and nob o dy w orks on it unless ev ery one else has sp en t at least as man y da ys w orking on it, ho w man y da ys (an in teger) did it tak e to write this test?
解析
- A shortest path is x ! x ! x ! x ! x ! x ! x ! x ! x ! x ! 400 800 1600 2000 x ! x ! x ! x , using 13 m ultipli ations .