Question

Расстояние между пристанями А и В равно 96 км. Из пристани А отправили плот по течению вниз. Одновременно с этим из пристани В отплыла моторная лодка и встретилась с ним через 4 часа. Какова собственная скорость лодки,если скорость течения равна 3 км/ч?

Answer 1

Problem Analysis

We are given the following information: - The distance between two ports, A and B, is 96 km. - A raft was sent downstream from port A. - At the same time, a motorboat left port B and met the raft after 4 hours. - The speed of the current is 3 km/h.

We need to find the speed of the motorboat.

Solution

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

Since the raft is moving downstream, its speed relative to the water is the sum of its own speed and the speed of the current. Therefore, the speed of the raft is (x + 3) km/h.

We know that the distance traveled by the raft is 96 km, and it took 4 hours to meet the motorboat. We can use the formula distance = speed × time to set up an equation:

(x + 3) × 4 = 96

Simplifying the equation, we have:

4x + 12 = 96

Subtracting 12 from both sides:

4x = 84

Dividing both sides by 4:

x = 21

Therefore, the speed of the motorboat is 21 km/h.

Answer

The speed of the motorboat is 21 km/h.