Sorry my ability of maths is not so good, could anyone could help me to solve this problem, thanks
There are 3 (k=3) countries teams
(eg, china, japan, korea)
Each team has 5 members.
These ppl need to line up in a row.
But each person should have at least one team member beside him.
How many number of ways can they arrange??
How about the general case when k=n countries?