along a railway line there are 20 stations the number of different tickets required in order so that it - Maths - Permutations and Combinations

Question

along a railway line there are 20 stations the number of different
tickets required in order so that it may be possible to travel from
every station to every station is

Rajat Sethi · Accepted Answer

Total no of stations =20
Being able to go from every station to every station, we have start
from 1st station and go from there to the rest 19 stations
Similarly,we can have to book ticket from all the 20 stations so
that we can go to the rest 19 stations respectively from each one
of them
So, total no of ways = 20 *19 =380

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