probability
2010-01-07 4:50 am
In a stall game, the whole surface of a table is covered by square tiles of side 6 cm. A participant is asked to throw a metal disc of diameter 4 cm on to the table. If the disc does not touch the side of any square , he wins. If it touches a side, he loses. Suppose a participant throws the disc and it stays on the table , what is the probability that he wins the game?
回答 (1)
2010-01-07 5:15 am
✔ 最佳答案
要 win , 個 disc 一定落在而且只落在某一個正方形之中,考慮 disc 的圓心,當個disc在左上角時,圓心離正方上邊 4/2 = 2 cm,
同理當 disc 在左下角,圓心離正方底邊 2 cm,
因此要disc不出界,圓心範圍是一個邊長為 6 - 2 - 2 = 2cm的正方形,
P(wins) = 2cm正方面積 / 6cm 正方面積
= 4 : 36
= 1/9
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原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20100106000051KK01572