Exams

Southern state Karnataka has been ranked top among the states in the country in terms of manufacturing excellence, according to a study by apex industry body Assocham in 2017.

As A1 speaks always after A2, they can speak only in  1st  to 9th places and 

A2 can speak in 2nd to 10 the places only when A1 speaks in 1st place 

A2 can speak in 9 places the remaining 

 A3, A4, A5,...A10  has no restriction. So, they can speak in 9.8! ways. i.e

when A2 speaks in the first place, the number of ways they can speak is 9.8!.

When A2 speaks in second place, the number of ways they can speak is  8.8!.

When A2 speaks in third place, the number of ways they can speak is  7.8!. When A2 speaks in the ninth place, the number of ways they can speak is 1.8!

Therefore,Total Number of ways they can  speak = (9+8+7+6+5+4+3+2+1) 8! = 92(9+1)8! = 10!/2