SOLUTION: you must select 4 units from a truck of 12. It is known that 3 units are defective. What is the probability that exactly two units are good? I appreciate any help! Since th

Algebra ->  Probability-and-statistics -> SOLUTION: you must select 4 units from a truck of 12. It is known that 3 units are defective. What is the probability that exactly two units are good? I appreciate any help! Since th      Log On


   



Question 554768: you must select 4 units from a truck of 12. It is known that 3 units are defective. What is the probability that exactly two units are good?
I appreciate any help! Since these events are dependent, I am having trouble.

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
you must select 4 units from a truck of 12. It is known that 3 units are defective. What is the probability that exactly two units are good?
I appreciate any help! Since these events are dependent, I am having trouble.
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P(2 good and 2 bad) = 9C2*3C2/12C4 = (36*3)/495 = 0.2182
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Cheers,
Stan H.