10 examination papers are arranged in such a way that the best and the worst papers never come together . The number of arrangements is?

Question

10 examination papers are arranged in such a way that the best
and the worst papers never come together The number of arrangements
is?

Rashmi Sinha · Answer

Total no of arrangement possible = 10!
Arrangement possible when 2 copies (best and of wrost) togather
= 9!*2
Arrangement possible when 2 are not together=10!-9!*2
=2903040