Question

По течению реки корабль плыл 5 часов, а против течения корабль проплыл ещё 3 часа. Найди скорость корабля, если известно, что по течению он проплыл на 108 км больше чем против течения, а скорость течения равна 3 км/я

Answer 1

Ответ:

5(х+3)-3(х-3)=108

5х+15-3х+9=108

2х=108-15-9

2х= 84

х= 84÷2

х=42км/ч скорость корабля

Answer 2

Problem Analysis

We are given that a ship traveled for 5 hours downstream (with the current) and an additional 3 hours upstream (against the current). We also know that the ship traveled 108 km more downstream than upstream, and the speed of the current is 3 km/h. We need to find the speed of the ship.

Downstream Speed Calculation

Let's assume the speed of the ship in still water is x km/h. When the ship is traveling downstream, its effective speed is the sum of its speed in still water and the speed of the current. Therefore, the ship's speed downstream is (x + 3) km/h.

Upstream Speed Calculation

When the ship is traveling upstream, its effective speed is the difference between its speed in still water and the speed of the current. Therefore, the ship's speed upstream is (x - 3) km/h.

Distance Calculation

The distance traveled downstream is the product of the ship's speed downstream and the time taken to travel downstream (5 hours). Similarly, the distance traveled upstream is the product of the ship's speed upstream and the time taken to travel upstream (3 hours). We are given that the distance traveled downstream is 108 km more than the distance traveled upstream.

Solution

To find the speed of the ship, we can set up the following equation based on the given information:

(x + 3) * 5 = (x - 3) * 3 + 108

Now, let's solve this equation to find the value of x.

Calculation

Expanding the equation, we get:

5x + 15 = 3x - 9 + 108

Combining like terms, we have:

5x - 3x = 108 - 9 - 15

Simplifying further, we get:

2x = 84

Dividing both sides by 2, we find:

x = 42

Therefore, the speed of the ship in still water is 42 km/h.

Answer

The speed of the ship is 42 km/h.