one coin is selected at random from a bag containing 12 coins,of which x are gold coins.
a)Find the probability of selecting a gold coin from the ag in terms of x.
b)When 6 additional gold coins are put into the bags,the probability of selecting a gold coin from the bag is doubles.Find the value of x.
PROBABILITY!!MATHS!!
2009-12-12 11:09 pm
回答 (1)
2009-12-12 11:12 pm
✔ 最佳答案
(a) P(selecting a gold coin from the bag)=x/12(b) P(selecting a gold coin from the bag after 6 additional gold coins are put into the bags)=(x+6)/(12+6)
Since 2P(selecting a gold coin from the bag)=P(selecting a gold coin from the bag after 6 additional gold coins are put into the bags)
2x/12=(x+6)/18
x/6=(x+6)/18
18x=6x+36
x=3
收錄日期: 2021-04-26 13:49:39
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