In how many ways can 5 boys and 3 girls be seated in a row such that all 3 girls are always together?

Explanation

Treat 3 girls as 1 unit. Total units = 5 boys + 1 girl-unit = 6 units. Arranged in 6! ways. 3 girls can be arranged among themselves in 3! ways. Total = 6! * 3! = 720 * 6 = 4320.