If six persons sit in a row, then the probability that three particular persons are always together is____________?
Q1. If six persons sit in a row, then the probability that three particular persons are always together is____________?
Answer: 01-May
Explanation: Treat 3 specific persons as one unit: 4 items can be arranged in 4! = 24 ways, and 3 persons can arrange internally in 3! = 6 ways; probability = 144/720 = 1/5.