SOLUTION: Printed circuit cards are placed in a functional test after being populated with semiconductor chips. A lot contains 21 cards, and 4 are selected without replacement for functional
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-> SOLUTION: Printed circuit cards are placed in a functional test after being populated with semiconductor chips. A lot contains 21 cards, and 4 are selected without replacement for functional
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Question 1130970: Printed circuit cards are placed in a functional test after being populated with semiconductor chips. A lot contains 21 cards, and 4 are selected without replacement for functional testing.
(Please enter your answers as fractions in lowest terms or as decimals rounded to four decimal places. Thank you!)
a. If 15 cards are defective, what is the probability that at least one defective card is in the sample?
b. If 14 cards are defective, what is the probability that at least one defective card is in the sample? Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! Find probability no defective cards are and subtract from one.
(6/21)(5/20)(4/19)(3/18)=(2/7)(1/4)(4/19)(1/6)=2/798=1/399
398/399 is the probability at least one card is defective.
(7/21)(6/20)(5/19)(4/18)=(1/3)(3/10)(5/19)(2/9)=1/171
so the probability is 1-1/171 or 170/171
