Yahoo奇摩 網頁搜尋

First find the probability that a page has at least 3 typos: = 1 - (probability of 0 typo + probability of 1 typo + probability of 2 typos) = 1 - [ 0.3^0/0! + 0.3^1/1! + 0.3^2/2! ] / e^(0.3) Let the answer be P, then the expected number of pages until you find one such...