rajdhani express from delhi to bombay stops at 9 intermediate stations 6 passengers enters the train during journey holding 6 different tickets of the same class.how many different sets of tickets they may have had. plz give full solution

Let S₁,S₂....S₉ be intermadiate stations

The person taking train from the station S_i(1≤i≤9) can get down any of the next (10-i) stations.

 Total no of possible tickets

=∑⁹_i=1(10-i) =45

The six different tickets must be out of these 45 tickets.

Required number of ways = ⁴⁵C₆ = ⁴⁵C₃₉  .