Sorry, 答案應該是2.22580645161

#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

所有跟帖： 

• 請看我上麵的無限次答案:0.69/0.31=2.225806452 -jinjing- ♀ (22 bytes) () 09/17/2014 postreply 10:20:27