回複：Quant 麵試題:梯子

來源: 於 2009-07-16 11:52:59 [博客] [舊帖] [給我悄悄話] 本文已被閱讀：次

Coin A: has 2 faces - face-up and face-down
Coin B: has 2 faces - face-down only

Simple strategy would be: if you get coin A, then keep it.
If you get coin B, then change to coin A. This means dump coin B whenever possible. The probability is same at each step. So the prob would be the multiplication of each one.