Suppose that you purchase randomly select 4 TV sets from a p

Suppose that you purchase (randomly select) 4 TV sets from a production run of 15 TV sets. Of the 15 TV sets, 11 are destined to last at least five years without needing a single repair. What is the probability that 3 of your TV sets will last at least five years without needing a single repair? (Round your answer to 4 decimal places.)

Solution

There are 15C4 ways to choose any four sets.

There are 11C3 ways to choose 3 taht will last 5 years, and 4 ways to choose 1 defective. Thus, there are (11C3)*4 ways to do this job.

Thus,

P(3 will last 5 years) = [(11C3)*4]/[15C4]

= 0.483516484 [ANSWER]