Question

Велосипедист ехал из одного города в другой сл скоростью 10км/ч.Если бы он ехал со скоростью на 20% больше,то приехал бы в город на 4ч раньше.Сколько км между городами

Answer 1

Пусть расстояние равно х
тогда в первом случае он проехал за
х/10 часов 

скорость изменилась стала 10+0.2*10=12км/4
тогда в первом случае он проехал за
х/12 часов

чтобы уравнять первый и второй случай нужно во втором случае прибавить 4 часа
х/12+4=х/10
10х+480=12х
2х=480
х=240 км
Ответ 240 км

Answer 2

Problem Analysis

We are given that a cyclist is traveling from one city to another at a speed of 10 km/h. If the cyclist were to travel at a speed 20% faster, they would arrive at the destination 4 hours earlier. We need to determine the distance between the two cities.

Solution

Let's assume the distance between the two cities is d km.

If the cyclist is traveling at a speed of 10 km/h, the time taken to cover the distance d is given by:

Time taken = d / 10 (Equation 1)

If the cyclist were to travel at a speed 20% faster, their speed would be 10 + (10 * 0.2) = 12 km/h. The time taken to cover the same distance d at this speed would be:

Time taken = d / 12 (Equation 2)

According to the problem, the difference in time taken between the two speeds is 4 hours. Therefore, we can set up the following equation:

d / 10 - d / 12 = 4 (Equation 3)

To solve for d, we can simplify Equation 3:

12d - 10d = 4 * 10 * 12 2d = 480 d = 240

Therefore, the distance between the two cities is 240 km.

Answer

The distance between the two cities is 240 km.