Sorry, 答案應該是2.22580645161

來源: 於 2014-09-16 17:40:13 [舊帖] [給我悄悄話] 本文已被閱讀：次

#Python code:

a = 0.69
b = 1 - a

average = 0
left = 1.0
i = 0

while i average += i * b * left
left = left * a
i = i + 1

print average