In this video tutorial I show you how to calculate how many arrangements or permutations when letters or items are restricted to being separated.
The following examples are given with worked solutions.
(1) In how many ways can 5 men and 3 women be arranged in a row if no two women are standing next to one another?
(2) In how many ways can the letters in the word SUCCESS be arranged if no two S’s are next to one another?

Permutations with restrictions - items not together | ExamSolutions - youtube Video