Math Main Page => Exercises - Math V-probability   Goal: to practise the probability of the events
Friday July 30 2010 07:14:02 PM		Friday July 30 2010 07:14:02 PM Flip Answers
[Assume one poll could poll out one and only one marble.]   If bagA contains marbles with three colors, 10 blue, 6 red and 12 green,     bagB contains marbles with three colors, 5 blue, 12 red and 8 brown,
1)	what's the probability of polling out one red marble in the first poll [From bagA]?		1) 10/28=5/14
2)	what's the probability of polling out one red marble first and then one blue marble in next poll [From bagA]?		2) (10*6)/(28*27)=5/63
3)	what's the probability of polling out three green marbles in the first three polls? [From bagA]		3) 12*11*10/(28*27*26)=55/819
4)	what's the probability of polling out one red or blue marble in the first poll? [From bagA]		4) 16/28=4/7
5)	what's the probability of polling out three marbles one by one and they all are different colors? [From bagA]		5) 6*10*6*12/(28*27*26)=20/91
6)	what's the probability of polling out one marble each from two bags and both are red?		6) 10*5/(28*25)=1/14
7)	what's the probability of polling out one marble each from two bags and both are same color?		7) (10*5+6*12)/(28*25)=61/350
8)	what's the probability of polling out one marble each from two bags and they are different colors?		8) 1-(10*5+6*12)/(28*25)=289/350
Score: ______________

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