12. BagA contain 4 white balls and 2 black balls . Bag B contains 2 white balls
and 3 black balls. A ball is drawn at random from bag A and is put in bag B.
Then a ball is drawn at random from B. What is the propability that the ball
drawn is black?
14. There are five cards ,numbered to 1 to 5,in a bag. Two cards are drawn
randomly without replacement .Find the probaility that the difference between
two numbers is greater than 2.
Probability
2007-12-08 7:36 am
回答 (3)
2007-12-08 7:57 am
✔ 最佳答案
12.probability of getting a black ball form bag a = 2/6
probability of getting a black ball form bag b = (3+1)6
so
2/6 乘 4/6 = 2/9
14.
總共有20款唔同既組合
12,13,14,15
21,23,24,25
31,32,34,35
41,42,43,45
51,52,53,54
相差大過2既 只有 14,15,25,41,51,52
so probability = 6/20 = 3/10
2007-12-08 10:18 am
12. P(the ball drawn is black)=3/6+1/6*2/6=7/12
14. C(2.5)=10;
P( difference between two numbers is greater than 2)=3/10
2007-12-08 02:30:11 補充：
14. C(2.5)=10; 大於2的組合有3個；P( difference between two numbers is greater than 2)=3/10
14. C(2.5)=10;
P( difference between two numbers is greater than 2)=3/10
2007-12-08 02:30:11 補充：
14. C(2.5)=10; 大於2的組合有3個；P( difference between two numbers is greater than 2)=3/10
2007-12-08 7:51 am
12. P(the ball drawn is black)=P(white, black) or P(black black)
=4/6 x3/(5+1) + 2/6 x4/6
=5/9
14.P( difference between two numbers is greater than 2)
=1/6x 2/5 x6
=2/5
=4/6 x3/(5+1) + 2/6 x4/6
=5/9
14.P( difference between two numbers is greater than 2)
=1/6x 2/5 x6
=2/5
收錄日期: 2021-04-25 16:20:42
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