There are 12 steamers plying between A and B. In how many ways could the round trip from A be made if the return was made on (i) the same steamer? (ii) a different steamer?
Given: 12 steamers plying between A and B.
To find: number of ways the round trip from A can be made.
i) The steamer which will go from A to B will be returning back,since the given condition is that same steamer should return.
There are 12 steamers available so there are 12 different ways to make around trip between A & B if done on same steamer.
ii)If the return trip is done on different steamer than the once used in trip on going from A to B then the possible number of ways are:12 × 11=132.
(11 because the once used in going from A to B cannot be used in returning hence, reduced by 1.)