Question

Пешеход прошёл расстояние от пункта С до пункта М за 3 часа. Возвращаясь, он первые 16 км шёл с той же скоростью, а затем снизил скорость на 1 км/ч, вследствие чего затратил на обратный путь на 4 минуты больше, чем на путь из С в М. Чему равно расстояние между пунктами С и М ?

Answer 1

Я не понимаю ¡¡¡¡¡¡!!!!!

Answer 2

Problem Analysis

We are given that a pedestrian walked from point C to point M in 3 hours. On the return journey, the pedestrian walked the first 16 km at the same speed and then reduced the speed by 1 km/h. As a result, the return journey took 4 minutes longer than the journey from C to M. We need to find the distance between points C and M.

Solution

Let's assume the distance between points C and M is d km.

From the given information, we can determine the following:

- The pedestrian walked the first 16 km at the same speed. - The pedestrian reduced the speed by 1 km/h for the remaining distance (d - 16) km.

We can calculate the time taken for the journey from C to M and the return journey using the formula:

Time = Distance / Speed

For the journey from C to M: - Time = 3 hours - Distance = d km - Speed = x km/h (let's assume the initial speed is x km/h)

So, we have the equation:

3 = d / x For the return journey: - Time = 3 hours and 4 minutes = 3 + 4/60 hours = 3.067 hours (approximately) - Distance = d km - Speed = (x - 1) km/h (speed reduced by 1 km/h)

So, we have the equation:

3.067 = 16 / x + (d - 16) / (x - 1) Now, we can solve these two equations to find the value of d.

Calculation

Let's solve equations and to find the value of d.

From equation we can express x in terms of d:

x = d / 3 Substituting equation into equation we get:

3.067 = 16 / (d / 3) + (d - 16) / ((d / 3) - 1)

Simplifying the equation further:

3.067 = 48 / d + (3d - 48) / (d - 3)

Multiplying through by d(d - 3) to eliminate the denominators:

3.067d(d - 3) = 48(d - 3) + (3d - 48)d

Expanding and simplifying:

3.067d^2 - 9.201d = 48d - 144 + 3d^2 - 48d

Combining like terms:

0.067d^2 - 54.201d + 144 = 0

Using the quadratic formula:

d = (-b ± √(b^2 - 4ac)) / (2a)

where a = 0.067, b = -54.201, and c = 144.

Solving this quadratic equation, we find two possible values for d: d1 and d2.

Calculation Results

Using the quadratic formula, we find the following values for d:

- d1 ≈ 0.9 km - d2 ≈ 213.6 km

Since the distance between points C and M cannot be negative, we can discard the negative value (d1).

Therefore, the distance between points C and M is approximately 213.6 km.

Answer

The distance between points C and M is approximately 213.6 km.