PP-T2-DS46

[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

[bezoeca]

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?
在三次flips中
有兩次heads up的機率
由於每次翻轉有正反兩種
所以翻轉三次:2^3=8
翻轉兩次HEADS UP的可能性為:head up,head up,tails up
此種排列有三
所以3/8=0.375

[Huang Hsin-Yi]

原來是這樣,謝謝
機率與組合的題目都會讓我暈~~~~~~~~