SOLUTION: I randomly take three lightbulbs from a box containing 80 lightbulbs of which 5 are defective. What is the probability that none of the three lightbulbs I take are defective? What

Algebra ->  Probability-and-statistics -> SOLUTION: I randomly take three lightbulbs from a box containing 80 lightbulbs of which 5 are defective. What is the probability that none of the three lightbulbs I take are defective? What      Log On


   

Question 440136: I randomly take three lightbulbs from a box containing 80 lightbulbs of which 5 are defective.
What is the probability that none of the three lightbulbs I take are defective? What is the
probability that at least one of the lightbulbs I take is defective?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

Note: The probability of x successes in n trials is: 

P = nCx* p%5Ex%2Aq%5E%28n-x%29 where p and q are the probabilities of success and failure respectively. 

In this case p(defective) = 5/80 =.0625    and q = .9375

  nCx = n%21%2F%28x%21%28n-x%29%21%29

randomly take three light bulbs from the box 

P(none are defective) = (.9375)^3 = .824

P(at least one is defective) =  1 - P(none are defective) = 1 -.824 = .176