Question

the no.of permutations of letters a,b,c,d such that b does not follow a ,and c does not follow b and. d does not follow c, is

Answer 1

Given: Letters a,b,c,d such that b does not follow a ,and c does not follow b and. d does not follow c.

To find: The no.of permutations of letters a,b,c,d according to the condition.

Solution:

• Now we have given 4 letters, a,b,c,d. So number of permutations of a, b, c, d will be:

                  4!= 24  

• Now as per the question:

• Number of permutations of ab, c, d will be:

                  3!= 6  

• Number of permutations of a, bc, d will be:

                  3!= 6  

• Number of permutations of a ,b ,cd will be:

                  3!= 6  

• Now, number of permutations of b and c will be: 2!= 2  

• Number of permutations of c and d will be: 2!= 2  

• Number of permutations of d and b will be: 2! =2  

• Number of permutations of b,c and d = 1  

• So now calculating the final part, we get:

                  4! - 3! - 3! - 3! + 2! + 2! + 2! - 1! = 11

Answer:

              So the number of permutations of letters a,b,c,d is 11.