Question

Расстояние между городами А и B равно 280 км. Из этих городов навстречудруг другу одновременно выехали два автобуса. Скорость одного автобусаравна 80 км/ч, скорость другого на 20 км/ч меньше. Через сколько часов автобусы встретятся?

Answer 1

1) 80-20=60
2) 80+60=140
3)280:140=2
Ответ:они встретяться через 2 часа

Answer 2

Problem Analysis

We are given that the distance between cities A and B is 280 km. Two buses start simultaneously from these cities towards each other. The speed of one bus is 80 km/h, while the speed of the other bus is 20 km/h less. We need to find out how many hours it will take for the buses to meet.

Solution

To find the time it takes for the buses to meet, we can use the formula:

Time = Distance / Relative Speed

The relative speed of the two buses is the sum of their individual speeds. Let's calculate the relative speed:

Relative Speed = Speed of Bus 1 + Speed of Bus 2

Since the speed of one bus is 80 km/h and the speed of the other bus is 20 km/h less, the relative speed can be calculated as:

Relative Speed = 80 km/h + (80 km/h - 20 km/h)

Now, let's calculate the time it takes for the buses to meet:

Time = Distance / Relative Speed

Substituting the given values:

Time = 280 km / Relative Speed

Let's calculate the relative speed and the time it takes for the buses to meet.

Calculation

Relative Speed = 80 km/h + (80 km/h - 20 km/h) = 80 km/h + 60 km/h = 140 km/h

Time = 280 km / 140 km/h = 2 hours

Therefore, the buses will meet after 2 hours.

Answer

The buses will meet after 2 hours.