Question

Plsee answer

A and B enters a line of 20 people randomly.
What is the probability that there are 6 people standing between A and B?

Answer 1

Drawing a diagram shows that there are 30 permutations where A and B have 6 people between them.
The number of permutations of A and B in the total of 22 people is
\[22P2=\frac{22!}{20!}\]
therefore the required probability is given by
\[30\times \frac{20!}{22!}=you\ can\ calculate\]