0.5*(1 - P[having 10k after n tosses]) ?
and
P[having 10k after 30 tosses]
= (30 choose 15)*(1/2)^30
P[having 10k after 100 tosses]
= (100 choose 50)*(1/2)^100
hehe
回複:Fun Probability Question 來源: TCT
本帖於 2009-12-19 10:42:34 時間, 由普通用戶 康MM 編輯