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

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) (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
==========================================
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
==========================================
iii)both are defective
# of ways to succeed: 2C2 = 1
# of possible: 45
P(2 defective) 1/45
==========================================
Cheers,
Stan H.

RELATED QUESTIONS
It is known that ther are two defective items in a group of ten.One item is selected and... (answered by stanbon)

it is knw that there are two deffective items in a group of ten. One item is selected and (answered by Positive_EV)

A lot consists of 20 defective and 80 non-defective items from which two items are... (answered by ikleyn,Edwin McCravy)

There are 1000 components in a box of which 10 are known to be defective. two... (answered by Edwin McCravy)

Five items are selected at random from a production line. What is the probability of... (answered by reviewermath)

I need help with part 2 of this question: A box contains 10 items, of which 3 are... (answered by stanbon)

In a sample of 10 discs, it is known that 2 are defective. Three discs are selected at... (answered by Theo)

In a box of 14 clocks, it is known that three clocks are defective. Two clocks are... (answered by nerdybill)

Suppose that it is known that 5% of the items produced by a particular machine are... (answered by stanbon)