SOLUTION: There are 4 white balls and 8 black balls in a box. If four balls are randomly selected. The probability that exactly 2 balls are white is:
a) 0.339
b) 0.406
c) 0.452
d)
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-> SOLUTION: There are 4 white balls and 8 black balls in a box. If four balls are randomly selected. The probability that exactly 2 balls are white is:
a) 0.339
b) 0.406
c) 0.452
d)
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Question 363823: There are 4 white balls and 8 black balls in a box. If four balls are randomly selected. The probability that exactly 2 balls are white is:
a) 0.339
b) 0.406
c) 0.452
d) Other:_______
The average number of black balls obtained when four balls are randomly selected is:
a) 2.333
b) 1.333
c) 2.667
d) Other : ______________
You can put this solution on YOUR website! There are 4 white balls and 8 black balls in a box. If four balls are randomly selected. The probability that exactly 2 balls are white is:
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Ans:
Pick 2 white: 4C2 = 6 ways
Pick 2 black: 8C2 = 28 ways
Pick 4 balls randomly: 12C4= 495
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P(exactly 2 white in 4) = (6*28)/495 = 0.339
a) 0.339
b) 0.406
c) 0.452
d) Other:_______
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The average number of black balls obtained when four balls are randomly selected is:
P(black) = 8/12 = 2/3
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Average black of 4 = (2/3)4 = 2.667
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Cheers,
Stan H.
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a) 2.333
b) 1.333
c) 2.667
d) Other : ______________
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