What is the probability that three specific individuals always sit together when six people are arranged in a row?

Explanation

There are 6! ways to arrange six people in a row. When the three particular individuals are considered as a single group, we effectively have 4 entities to arrange, which can be done in 4! ways. Inside this group, the three individuals can be arranged among themselves in 3! ways. Therefore, the total favorable arrangements are 3! × 4!. The required probability is (3! × 4!) / 6! = 1/5.