How to arrange 6 people but two are joined and two are seperated

39 Views Asked by At

We have 6 people lined up. 2 are best friends say A and B and are always next to each other and we have 2 other dudes C and D who are always separated. Independently I know that there are 240 ways you can pair A and B together and 480 ways you can keep C and D separated but I don't know how to put this together

1

There are 1 best solutions below

3
On BEST ANSWER

Hint: Consider A and B as 1 person and find the number of ways of arranging 5 people. Now multiply that by 2 as A and B can themselves exchange positions.

Now, consider A and B as a single person and C and D as a single person too and find the ways of arranging 4 people. Multiply that by 4 as A, B, C and D can internally change positions.

Subtract the second case from first to reach your answer.