# The number of permutations of 1,2,3,4,5,6 such that pattern 12,23,34,45,56 do not appear in the permutation is ?

Sep 12, 2017

$25$

#### Explanation:

Number of permutations of 6 objects taken 2 at a time:

(6!)/(4!) = 30

$12 , 23 , 34 , 45 , 56$

is 5 permutations.

So:

(6!)/(4!) - 5 = 25