SOLUTION: A lot of portable radios contains 15 good radios and 3 defective ones. If two are selected and tested, find the probability that at least one will be defective.

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Question 328033: A lot of portable radios contains 15 good radios and 3 defective ones. If two are selected and tested, find the probability that at least one will be defective.

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Good : 15
Bad:3
Total:18
.
.
P(at least one bad)+P(both good)=1
P(at least one bad)=1-P(both good)
P(both good)=%2815%2F18%29%2814%2F17%29=70%2F102
P(at least one bad)=1-70%2F102=102%2F102-70%2F102=32%2F102=16%2F51