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

The distance between a and B is 70 km. There are two cars starting from the two places at the same time and continuously going back and forth between a and B. the first car departing from a is 30 km per hour, and the second car departing from B is 40 km per hour. When the first car departing from a departs from a for the second time, it meets the second car, and the two cars are separated They drove separately______ Kilometer and______ Kilometers

Let two cars run for X hours. (40 + 30) x = 5 × 70, 70X = 350, x = 5. The first car: 30 × 5 = 150 (km); the second car: 40 × 5 = 200 (km)

There is a bus between a and B

A bus between a and B stops at five stops (including a and b). If the distance between the stops and between a and B is not equal, how many different fares do you think there are for the whole journey between a and B? How many kinds of tickets do you need to prepare?
Ticket: 5 × 4 / 2 = 10 kinds

The bus No.20 of a city goes back and forth between a and B, and both of them send a car at the same time interval. A cyclist walks forward at the same speed. Every 15 minutes, a bus passes behind, and every 10 minutes, a bus comes face to face. How many minutes does the bus Send a car from two places?

1 ÷ [(1 / 15 + 1 / 10) △ 2] = 12 (minutes)