og12 ps 174

Kath1985 · 发表于 2011-2-23 21:43:59

[attachimg=452,446]84961[/attachimg]
答案D 我的想法是1/2*1/2*1.2=1/8
請問哪裡錯了求好心人詳解感謝

sdcar2010 · 发表于 2011-2-23 22:10:47

You toss three times, you get 8 total possibilities.

Among them there is only one possibility that no TAIL was up: head, head, head.

So the probability of having at least one tail up is 7/8.

Kath1985 · 发表于 2011-2-24 22:28:24

所以我算出來的1/8是head head head囉 ?

lyuki · 发表于 2011-2-25 05:34:25

AT LEAST means
1 - every time HEAD
= 1 - 1/8 = 7/8

Kath1985 · 发表于 2011-2-27 21:43:17

i see thank you ^^

og12 ps 174

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