Question

Из города A в город В двигался автобус. Первую половину пути он проехал со скоростью на 20 км/ч меньше , чем скорость во второй части пути. Первую половину пути автобус проехал за 10 часов , а вторую -за 8 . Найдите расстояние между городами А и В

Answer 1

Х км - расстояние между городами А и В
х/2 : 10 =х/20  км/ч - скорость в первой части пути
х/2 : 8 = х/16  км/ч - скорость во второй части пути

Уравнение
х/16 - х/20 = 20
(5х-4х)/80 = 20
х/80 = 20
х= 20 · 80
х = 1600 км - расстояние между городами А и В
Ответ: 1600 км.

Answer 2

Problem Analysis

We are given that a bus traveled from city A to city B. The bus traveled the first half of the distance at a speed 20 km/h slower than the speed in the second half. The bus took 10 hours to cover the first half and 8 hours to cover the second half. We need to find the distance between city A and city B.

Solution

Let's assume the speed of the bus in the second half of the journey is x km/h. Then the speed in the first half of the journey would be x - 20 km/h.

We can use the formula distance = speed × time to calculate the distance traveled in each half of the journey.

In the first half of the journey: - Speed = x - 20 km/h - Time = 10 hours

In the second half of the journey: - Speed = x km/h - Time = 8 hours

We can set up the following equations:

Distance in the first half = (x - 20) × 10

Distance in the second half = x × 8

The total distance between city A and city B is the sum of the distances in the first and second halves.

Total distance = Distance in the first half + Distance in the second half

Let's solve these equations to find the distance between city A and city B.

Calculation

Distance in the first half = (x - 20) × 10

Distance in the second half = x × 8

Total distance = Distance in the first half + Distance in the second half

Substituting the values:

Total distance = (x - 20) × 10 + x × 8

Simplifying the equation:

Total distance = 10x - 200 + 8x

Total distance = 18x - 200

To find the value of x, we need more information. The given information is not sufficient to determine the value of x and, consequently, the total distance between city A and city B.

Therefore, we cannot find the distance between city A and city B with the given information.

Please let me know if there is anything else I can help you with.