Question

Катер проходить відстань між двома пристанями, яка дорівнює 224км, за течією річки за 7 год. за скільки годин він пройде цю відстань проти течії, якщо швидкість течії становить 2км/год.?

Answer 1

1) 224:7=32 км/год - швидкість за теч
2) 32-2=30 км/год - власна шв катера
3)30-2=28 км/год - швид кат проти течії
4)224:28=8 год - пройде проти течії

Answer 2

Problem Analysis

We are given the following information: - The distance between two ports is 224 km. - A boat travels this distance downstream (with the current) in 7 hours. - The speed of the current is 2 km/h.

We need to determine how long it will take for the boat to travel the same distance upstream (against the current).

Solution

To solve this problem, we can use the concept of relative speed. The speed of the boat relative to the water is the difference between the boat's speed and the speed of the current.

Let's denote the speed of the boat as B km/h and the speed of the current as C km/h.

When the boat is traveling downstream, its effective speed is the sum of its speed and the speed of the current: (B + C) km/h.

When the boat is traveling upstream, its effective speed is the difference between its speed and the speed of the current: (B - C) km/h.

We can use the formula distance = speed × time to calculate the time it takes for the boat to travel a certain distance.

Calculation

Given: - Distance = 224 km - Time downstream = 7 hours - Speed of the current = 2 km/h

Let's calculate the speed of the boat downstream: - Distance downstream = 224 km - Time downstream = 7 hours - Speed downstream = Distance downstream / Time downstream = 224 km / 7 hours = 32 km/h

The speed of the boat relative to the water downstream is the sum of the boat's speed and the speed of the current: - Speed downstream = Boat speed + Current speed - 32 km/h = Boat speed + 2 km/h - Boat speed = 32 km/h - 2 km/h = 30 km/h

Now, let's calculate the time it takes for the boat to travel the same distance upstream: - Distance upstream = 224 km - Speed upstream = Boat speed - Current speed = 30 km/h - 2 km/h = 28 km/h - Time upstream = Distance upstream / Speed upstream = 224 km / 28 km/h = 8 hours

Answer

The boat will take 8 hours to travel the distance of 224 km upstream against the current, given that the speed of the current is 2 km/h.