SOLUTION: in a shipment of 30 televisions, 4 are defective. if 3 television sets are randomly selected and tested without replacement, what is the probability that the three are defective?

Hi

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

P = nCx*  where p and q are the probabilities of success and failure respectively. 

In this case let p(defective) = 4/30 = 2/15 & q = 7/15

nCx = 

P(3 chosen are all defective) = (2/15)^3 = .0024