PP-PS-T2-46

[whoisallan]

46. 5979-!-item-!-187;#058&004694
If a coin has an equal probability of landing heads up or tails up each time it is flipped, what is the probability that the coin will land heads up exactly twice in 3 consecutive flips

(A) 0.125
(B) 0.25
(C) 0.375
(D) 0.50
(E) 0.666

ANS: C

請問該如何解題?

[whoisallan]

不好意思, 已找到解答...自貼如下

http://www.formosamba.com/phpBB3/viewtopi ... t=coin+has