If the train between a and B stops at three stations, there will be______ Different fares (same round-trip fare) need to be prepared______ I want to buy a ticket

If the train between a and B stops at three stations, there will be Different fares (same round-trip fare) need to be prepared I want to buy a ticket

This question is equivalent to how many different fares there are in a line segment with three points, that is, how many lines there are: 4 + 3 + 2 + 1 = 10; how many kinds of tickets need to be considered in order, 10 × 2 = 20

How many different fares are there for the passenger trains between a and B stopping at three stations
How many different fares are there for a passenger train between a and B stopping at three stops (assuming that the train has only hard seats and the distance is different)

This is a permutation! There are 5 stations from a to B, C52 = 5 * 4 / 2 = 10
There are 10 different kinds of tickets, and there are also 20 kinds of tickets from place B, that is, 10 * 2

If a train between a and B stops at three stations, the Railway Bureau will set up different fares and prepare tickets

This is a permutation and combination calculation problem, let's analyze: there are three stations on the way, plus the terminal at both ends, a total of five stations, any two stations have to have two kinds of tickets (different directions). And the combination calculation formula of any two of the five numbers is: 5! / (3! * 2!) = 10, that is, there are 10 kinds of fares, but the round-trip