SOLUTION: It is known that there are two defective items in a group of ten.One item is selected and then a second without replacing the first item. What is the probability that i)both item

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Question 696929: It is known that there are two defective items in a group of ten.One item is selected and then a second without replacing the first item.
What is the probability that
i)both items are good
ii)the second one is defective
iii)both are defective
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
It is known that there are two defective items in a group of ten.One item is selected and then a second without replacing the first item.
What is the probability that
i)both items are good
# of ways to succeed: 8C2 = 28
# of possible outcomes: 10C2 = 45
P(2 good) = 28/45
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ii)the second one is defective
# of ways to succeed: 8*2 + 9*1 = 25
# of possible outcomes: 45
P(2nd is defective) = 25/45 = 5/9
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iii)both are defective
# of ways to succeed: 2C2 = 1
# of possible: 45
P(2 defective) 1/45
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Cheers,
Stan H.