Question

A manufacturing plant produces a batch of 10 containers out of which 4 are defective. in a quality inspection test, 3 containers are chosen at random. what is the probability that at least one would be defective

Answer 1

Total number of containers = 10

Total number of defective containers = 4

Find the number of non-defective containers:

Total number of non-defective container = 10 - 4 = 6

Find the probability that none of the 3 are defective:

P(none of the 3 chosen are defective) = (6/10)(5/11)(4/10) = 6/55

Find the probability that at least 1 is defective:

Probability that at least 1 is defective = 1 - none is defective

Probability that at least 1 is defective = 1 - 6/55 = 49/55

Answer: The probability is 49/55