Question

Катер имеющий собственную скорость 15 км/ч, проплыл 2 часа по течению реки. На обратный путь он затратил 3 часа. Какова скорость течения реки?

Answer 1

1)15*2=30км-путь
2)30:3=10км/ч-скорость против течения
3)15-10=5км/ч-скорость течения

Answer 2

Problem Analysis

We are given that a boat with a speed of 15 km/h traveled for 2 hours downstream and 3 hours upstream on a river. We need to determine the speed of the river's current.

Solution

Let's assume the speed of the river's current is x km/h.

When the boat is traveling downstream, its effective speed is the sum of its own speed and the speed of the current. Therefore, the boat's effective speed downstream is 15 + x km/h.

When the boat is traveling upstream, its effective speed is the difference between its own speed and the speed of the current. Therefore, the boat's effective speed upstream is 15 - x km/h.

We can use the formula speed = distance / time to calculate the distance traveled in each case.

For the downstream journey, the distance traveled is (15 + x) * 2 km.

For the upstream journey, the distance traveled is (15 - x) * 3 km.

Since the distance traveled in both cases is the same (as it is a round trip), we can set up the following equation:

(15 + x) * 2 = (15 - x) * 3

Simplifying the equation:

30 + 2x = 45 - 3x

5x = 15

x = 3

Therefore, the speed of the river's current is 3 km/h.

Answer

The speed of the river's current is 3 km/h.