There are 12 people quarantined, with 3 known to have coronavirus. The probability of finding X people with coronavirus out of the 12 follows a binomial distribution. The probability that none of 5 randomly selected people from the quarantine have coronavirus is (9/12)*(8/11)*(7/10)*(6/9)*(5/8). The probability that none of 2 randomly selected people from the quarantine have coronavirus is (9/12)*(8/11).