Question

За 30 минут катер проходит по течению реки 4.5 км. найти скорость течения реки если скорость катера в 1.5 раза больше. чем против течения

Answer 1

1)  30мин. = 1/2 часа
     4,5 : 1/2 = 9км/ч - скорость лодки по течению
2) 9 : 1,5 = 6(км/ч) - скорость лодки против течения
3) (9 - 6) : 2 = 1,5(км/ч)
Ответ: 1,5 км/ч - скорость течения реки.

Answer 2

Calculating River Current Speed

To find the speed of the river's current, we can use the formula: Boat's speed downstream = Boat's speed in still water + River's current speed and Boat's speed upstream = Boat's speed in still water - River's current speed

Given that the boat's speed downstream is 4.5 km in 30 minutes and the boat's speed is 1.5 times faster than the speed against the current, we can calculate the river's current speed.

Calculating Boat's Speed in Still Water

Let's denote the boat's speed in still water as b and the river's current speed as c.

Given: - Boat's speed downstream = 4.5 km in 30 minutes - Boat's speed is 1.5 times faster than the speed against the current

We can set up the following equations: 1. b + c = 4.5 / (30/60) 2. b - 1.5c = 4.5 / (30/60)

Solving these equations will give us the boat's speed in still water and the river's current speed.

Solving the Equations

Let's solve the equations to find the boat's speed in still water and the river's current speed.

1. From equation 1: b + c = 9 km/h 2. From equation 2: b - 1.5c = 9 km/h

We can solve these equations to find the values of b and c.

Solution

The boat's speed in still water is 9 km/h and the river's current speed is 3 km/h.

This means that the boat's speed in still water is 9 km/h and the river's current speed is 3 km/h.