Question

Скорость моторной лодки по течению реки 30 км/ч,а протев течения 26 км/ч.найти скорость течения реки. Собственая скорсть теплохода 28 км/ч.теплаход плыл по течению реки 4 часа.скорость течения реки 3 км/ч.какое расстояние проплыл теплоход за это время?

Answer 1

To find the speed of the river current, we can use the formula:

Speed of boat in still water = Speed of boat with current + Speed of current

Let's calculate the speed of the river current first.

Given: - Speed of the boat downstream (with the current) = 30 km/h - Speed of the boat upstream (against the current) = 26 km/h

Using the formula, we can calculate the speed of the river current:

Speed of current = (Speed of boat downstream - Speed of boat upstream) / 2

Substituting the given values:

Speed of current = (30 km/h - 26 km/h) / 2 = 2 km/h

So, the speed of the river current is 2 km/h.

Now, let's calculate the distance traveled by the boat in 4 hours with a river current speed of 3 km/h.

Given: - Speed of the boat in still water = 28 km/h - Speed of the river current = 3 km/h - Time = 4 hours

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

Distance = Speed × Time

The effective speed of the boat with the current can be calculated as:

Effective speed = Speed of boat in still water + Speed of current

Substituting the given values:

Effective speed = 28 km/h + 3 km/h = 31 km/h

Now, we can calculate the distance traveled:

Distance = Effective speed × Time = 31 km/h × 4 hours = 124 km

Therefore, the boat traveled a distance of 124 km in 4 hours with a river current speed of 3 km/h.

Please let me know if there's anything else I can help you with!