On a raiway there are 10 stations. The number of types of tickets required in order that it may be possible to book a passenger from every staton to every other is

On a railway there are 10 stations. The number of types of tickets required in order that it may be possible to book a passenger from every station to every other is

On a railway track, there are 20 stations. The number of tickets required in order that it may be possible to book a passenger from every station to every other is

On a railway route there are 15 stations. The number of tickets required in order that it may be possible to book a passenger from every station to every other is

On a railway there are 20 stations. The number of different tickets required in order that it may be possible to travel from every station to every station is

On a railway there are 20 stations. The number of different tickets required in order that it may be possible to travel from every station to every station is

On a railway there are 20 stations. The number of different tickets required in order that it may be possible to travel from every station to every station is

On a railway there are 20 stations.The number of different tickets required in order that it may be possible to travel from every station to every station is

On a railway there are 20 stations. The number of different tickets required in order that it may be possible to travel from every station to every station is :

On a railway route there are 20 stations. What is the number of different tickets required in order that it may be possible to travel from every station to every other station