Question

Катер за 1,4 часа по течению реки прошел на 2,2 км меньше,чем за 1,7 часа против течения.найдите скорость течения реки,если скорость катера в стоячей воле равна 28 км/ч?

Answer 1

1,4 * ( 28 + X ) + 2,2 = 1,7 * ( 28 - X ) 39,2 + 1,4X + 2,2 = 47,6 - 1,7X 1,4X + 41,4 = 47,6 - 1,7X 1,4X + 1,7X = 47,6 - 41,4 3,1X = 6,2 X = 2 (  км/час ) - скорость течения реки ОТВЕТ 2 км/час

Answer 2

Problem Analysis

We are given the following information: - A boat travels on a river. - It takes 1.4 hours to travel downstream (with the current) a distance that is 2.2 km less than the distance it travels upstream (against the current) in 1.7 hours. - The speed of the boat in still water is 28 km/h.

We need to find the speed of the river's current.

Solution

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

To solve this problem, we can use the formula: distance = speed × time.

Let's calculate the distance traveled downstream and upstream.

The distance traveled downstream is given by: distance_downstream = (28 + x) × 1.4 km.

The distance traveled upstream is given by: distance_upstream = (28 - x) × 1.7 km.

According to the problem, the distance traveled downstream is 2.2 km less than the distance traveled upstream. So we have the equation:

distance_downstream = distance_upstream - 2.2 km.

Substituting the values, we get:

(28 + x) × 1.4 = (28 - x) × 1.7 + 2.2.

Now, let's solve this equation to find the value of x.

Calculation

Let's simplify the equation and solve for x:

(28 + x) × 1.4 = (28 - x) × 1.7 + 2.2.

Expanding the equation:

39.2 + 1.4x = 47.6 - 1.7x + 2.2.

Combining like terms:

1.4x + 1.7x = 47.6 - 2.2 - 39.2.

Simplifying:

3.1x = 6.2.

Dividing both sides by 3.1:

x = 6.2 / 3.1.

Calculating:

x = 2.

Answer

The speed of the river's current is 2 km/h.

Please note that this solution assumes a linear relationship between the speed of the boat and the speed of the river's current. In reality, the relationship may be more complex and depend on various factors.