Question

9. Решите задачу, используя формулы, выражающие зависимость между скоростями при движении по реке. Расстояние между двумя пристанями 252 км. теплоход прошёл это расстояние вниз по течению реки за 9 ч. Сколько времени теплоход затратил на обратный путь, если скорость течения реки 5 км/ч ?

Answer 1

Ответ:

Пошаговое объяснение:

Пусть х это скорость парохода

252/(х+5)=9

9х+45=252

9х=207

х=23

Answer 2

Problem Statement

We are given the following information: - Distance between two piers: 252 km - Time taken to travel downstream: 9 hours - Speed of the river current: 5 km/h

We need to find the time taken to travel upstream.

Solution

To solve this problem, we can use the formula that relates the speeds when traveling on a river: Speed downstream = Speed of the boat + Speed of the river current Speed upstream = Speed of the boat - Speed of the river current

Let's assume the speed of the boat is 'x' km/h.

Using the formula for speed downstream, we can write: x + 5 = (252 km) / (9 hours)

Simplifying the equation, we have: x = (252 km) / (9 hours) - 5 km/h

Now, we can calculate the speed of the boat: x = 28 km/h

Using the formula for speed upstream, we can write: 28 km/h - 5 km/h = (252 km) / t

Simplifying the equation, we have: 23 km/h = (252 km) / t

To find the time taken to travel upstream, we can rearrange the equation as: t = (252 km) / (23 km/h)

Calculating the value, we get: t ≈ 10.96 hours

Therefore, the time taken to travel upstream is approximately 10.96 hours.