Bob has lost 10 socks under his bed. Although there are 4 red socks, 4 blue socks and 2 pink socks. He is unable to see the colours. How many must he pull out before he is sure of getting a matching pair?
if can, please explain your answer...
thank you!
思考題 (數學)
2009-05-16 1:10 am
回答 (2)
2009-05-16 1:28 am
✔ 最佳答案
If he is lucky, he need two time to pull out the same sock. If he is unlucky, he need to pull four time to pull out the same sock.
First time, any sock
Second time, any sock which is different from the first one.
Third time, any sock which is different from the first and second one.
Last time, fourth time, any sock he pull up much match with one of the above three socks.
Hope it helps.
2009-05-16 9:28 pm
你係問抽到ga機會率?抽幾多個?英文差
收錄日期: 2021-05-01 09:49:54
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