P2-PS-46

[Huang Hsin-Yi]

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

拜求思路

[sunnyblue13s]

我覺得這是題目理解上的難題~~
twice - 兩回 in 3 consecutive flips

正正反 正反正 反正正

3/8=0.375

[Huang Hsin-Yi]

阿哈!

最簡單的方法就最快的方法,謝拉