A box contains 2 red, 3 yellow and 4 blue balls. Three balls are drawn in succession with replacement. Find the probability that
a) all are yellow
b) the first is red, the second is yellow and the third is blue
c) none are yellow
F.6 maths(3)
2010-03-30 7:23 am
回答 (1)
2010-03-30 7:49 am
✔ 最佳答案
a) For each draw, P(yellow) = 3/9 = 1/3Hence P(all 3 yellow) = (1/3)3 = 1/27
b) P(First red) = 2/9
P(Second yellow) = 1/3
P(Third blue) = 4/9
Hence required prob = 2/9 x 1/3 x 4/9 = 8/243
c) P(Not yellow) = 2/3 for each draw
So required prob = (2/3)3 = 8/27
參考: Myself
收錄日期: 2021-04-24 23:20:29
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