Question

Скорость лодки в стоячей воде 5 км в ч. Она плыла 6 ч по течению реки и 3 ч против течения. Какое расстояние проплыла лодка за всё время если скорость течения реки составляет 2 км в ч?​

Answer 1

Выражение: (5 + 2) · 6 + (5 - 2) · 3.

1) 5 + 2 = 7 км/ч - скорость лодки по течению реки;

2) 5 - 2 = 3 км/ч - скорость лодки против течения реки;

3) 7 · 6 = 42 км - плыла лодка по течению реки;

4) 3 · 3 = 9 км - плыла лодка против течения реки;

5) 42 + 9 = 51 км - расстояние, которое проплыла лодка за всё время.

Ответ: 51 км.

Answer 2

Calculation of Distance Traveled by the Boat

To calculate the distance traveled by the boat, we need to consider the time spent traveling with the current and against the current.

Given information: - Speed of the boat in still water: 5 km/h - Time spent traveling with the current: 6 hours - Time spent traveling against the current: 3 hours - Speed of the river current: 2 km/h

To calculate the distance traveled with the current, we can use the formula:

Distance = Speed × Time

The speed of the boat with the current is the sum of the speed of the boat in still water and the speed of the current:

Speed with current = Speed of boat + Speed of current

Substituting the given values:

Speed with current = 5 km/h + 2 km/h = 7 km/h

Therefore, the distance traveled with the current is:

Distance with current = Speed with current × Time with current = 7 km/h × 6 hours = 42 km.

To calculate the distance traveled against the current, we can use the same formula:

Distance = Speed × Time

The speed of the boat against the current is the difference between the speed of the boat in still water and the speed of the current:

Speed against current = Speed of boat - Speed of current

Substituting the given values:

Speed against current = 5 km/h - 2 km/h = 3 km/h

Therefore, the distance traveled against the current is:

Distance against current = Speed against current × Time against current = 3 km/h × 3 hours = 9 km.

To calculate the total distance traveled by the boat, we sum the distances traveled with and against the current:

Total distance = Distance with current + Distance against current = 42 km + 9 km = 51 km.

Therefore, the boat traveled a total distance of 51 kilometers during the given time period.

Please note that the above calculations assume a constant speed of the boat and the current throughout the entire journey.