Question

1 Скорость течения реки 5км/час, собственная скорость лодки 15 км/час. Найдите скорость движения лодки по течению реки и путь, по течению реки, пройденный лодкой за 3 часа. Сколько времени понадобится лодке вернуться на пристань, от которой она отправилась в путь по течению реки.ПОМОГИТЕ ПОЖАЛУЙСТА!

Answer 1

Сначало 15+5=20(км/ч)-скорость
потом 20*3=60(км) за 3 часа
получается что обратно лодка вернулась тоже за три часа

Answer 2

Calculation of Boat's Speed and Distance Traveled

To find the speed of the boat in still water and the distance traveled by the boat in 3 hours, we can use the following formulas:

Speed of the boat in still water (B): B = (Speed of the boat + Speed of the current) / 2

Distance traveled by the boat in 3 hours (D): D = Speed of the boat in still water * Time

Given: - Speed of the current = 5 km/h - Speed of the boat = 15 km/h - Time = 3 hours

Using the formula for the speed of the boat in still water, we can calculate:

Speed of the boat in still water (B): B = (15 km/h + 5 km/h) / 2 = 20 km/h / 2 = 10 km/h

Now, using the formula for the distance traveled by the boat, we can calculate:

Distance traveled by the boat in 3 hours (D): D = 10 km/h * 3 hours = 30 km

Therefore, the speed of the boat's movement relative to the current is 10 km/h, and the boat will travel a distance of 30 km in 3 hours.

Calculation of Time to Return to the Starting Point

To calculate the time it will take for the boat to return to the starting point, we need to consider the speed of the boat and the speed of the current.

Since the boat is moving against the current when returning to the starting point, we need to subtract the speed of the current from the speed of the boat to get the effective speed of the boat.

Given: - Speed of the current = 5 km/h - Speed of the boat = 15 km/h

The effective speed of the boat when moving against the current is:

Effective speed of the boat (E): E = Speed of the boat - Speed of the current = 15 km/h - 5 km/h = 10 km/h

To calculate the time it will take for the boat to return to the starting point, we can use the formula:

Time to return to the starting point (T): T = Distance / Effective speed of the boat

Since the boat has traveled a distance of 30 km, we can calculate:

Time to return to the starting point (T): T = 30 km / 10 km/h = 3 hours

Therefore, it will take the boat 3 hours to return to the starting point.