How many ways can be stack n different coins so that two particular coins are not adjacent to each other?
Answers
Answered by
5
Answer:
(n - 1)!(n - 2)
Step-by-step explanation:
n coin can be stacked in n! ways
If two particular coins are together then taking them as one unit, the number of coins to be arranged are n-1 and the two coins themselves can be arranged in 2! ways
Therefore,
Total arrangements when two coins are together = (n - 1)!2!
Number of ways, the two coins can be stacked that two particular coins are not together
= n! - (n - 1)!2!
= n(n - 1)! - (n - 1)!2!
= (n - 1)!(n - 2)
Similar questions