Question

За 4 часа езды на автомашине и 7 часов езды на поезде туристы проехали 640 км. Какова скорость поезда, если она на 5 км/ч больше скорости автомашины?(решение с помощтю системы уравнений.)

Answer 1

X-скорость автомашины
у-скорость поезда
4х+7у=640        4х+7у=640       4х+7у=640             
у-х=5                -х+у=5             -4х+4у=20    *4
11х=660
х=60        у=65
Ответ: 60 км/ч скорость автомобиля, а скорость поезда 65км/ч

Answer 2

Problem Analysis

We are given that tourists traveled a total distance of 640 km, with 4 hours of driving by car and 7 hours of train travel. The speed of the train is 5 km/h faster than the speed of the car. We need to find the speed of the train.

Solution

Let's assume the speed of the car is x km/h. Then the speed of the train is x + 5 km/h.

The distance traveled by the car can be calculated using the formula distance = speed × time. Therefore, the distance traveled by the car is 4x km.

Similarly, the distance traveled by the train is 7(x + 5) km.

According to the problem, the total distance traveled is 640 km. Therefore, we can write the equation:

4x + 7(x + 5) = 640

Simplifying the equation:

4x + 7x + 35 = 640

11x + 35 = 640

11x = 640 - 35

11x = 605

x = 605 / 11

x ≈ 55

Therefore, the speed of the car is approximately 55 km/h.

Since the speed of the train is 5 km/h faster than the speed of the car, the speed of the train is approximately 55 + 5 = 60 km/h.

Answer

The speed of the train is approximately 60 km/h.