Question

За 5 часов по течению реки теплоход проходит тот же путь, что за 7 часов против течения. Найдите собственную скорость теплохода, если скорость течения реки 3 км/ч.

Answer 1

Ответ:

Пошаговое объяснение:

1) 5 (х+3)=7(х-3)

2) 5х+15=7х-21

3) 2х=-21-15

4)2х=36

5)х=18

Answer 2

Ответ:5*(х+3)=7,(х-3) или 5*х+15=7*х-21 или 36=2*х или х=18 км/час.

Ответ 18 км/час.

Пошаговое объяснение:

Answer 3

Problem Analysis

We are given that a boat takes 5 hours to travel a certain distance downstream and 7 hours to travel the same distance upstream. We need to find the speed of the boat if the speed of the river current is 3 km/h.

Downstream Speed Calculation

Let's assume the speed of the boat is B km/h. When the boat is traveling downstream, its effective speed is the sum of its own speed and the speed of the river current. Therefore, the effective speed downstream is B + 3 km/h.

Upstream Speed Calculation

When the boat is traveling upstream, its effective speed is the difference between its own speed and the speed of the river current. Therefore, the effective speed upstream is B - 3 km/h.

Distance Calculation

Since the boat travels the same distance in both directions, we can set up the equation:

Distance = Speed x Time

Let's denote the distance as D km. We can write the equations as follows:

Downstream: D = (B + 3) x 5

Upstream: D = (B - 3) x 7

Solving the Equations

We can solve these equations to find the value of B.

Downstream: D = (B + 3) x 5

Upstream: D = (B - 3) x 7

Since the distance is the same in both equations, we can set them equal to each other:

(B + 3) x 5 = (B - 3) x 7

Simplifying the equation:

5B + 15 = 7B - 21

2B = 36

B = 18

Therefore, the speed of the boat is 18 km/h.

Answer

The speed of the boat is 18 km/h.