Question

Решение текстовых задач с помощью уравнений. Урок 4 Путешественники плыли на лодке из пристани А в пристань В по течению реки за 1,5 часа. После 30 минутной остановки на пристани B, они вернулись в пристань А за 1,5 часа на катере, скорость которого в 2 раза больше скорости лодки. Скорость реки равна 4 км/ч.​

Answer 1

Ответ:вот держи:3

Объяснение :

Ху...кхм так проехали

Answer 2

Problem Analysis

To solve this problem, we need to find the speed of the boat and the speed of the motorboat. We are given that the boat traveled from port A to port B with the current in 1.5 hours, and then returned from port B to port A on a motorboat in 1.5 hours. The speed of the river is given as 4 km/h.

Let's assume the speed of the boat is x km/h and the speed of the motorboat is 2x km/h.

Solution

To find the speed of the boat and the motorboat, we can use the formula:

Speed = Distance / Time

# Boat's Journey from Port A to Port B

The boat traveled from port A to port B with the current in 1.5 hours. The distance between the two ports can be calculated using the formula:

Distance = Speed × Time

The speed of the boat is x km/h, and the time taken is 1.5 hours. Therefore, the distance traveled by the boat from port A to port B is:

Distance_AB = x × 1.5

# Boat's Journey from Port B to Port A on a Motorboat

After a 30-minute stop at port B, the travelers returned from port B to port A on a motorboat in 1.5 hours. The distance between the two ports is the same as before. The speed of the motorboat is 2x km/h, and the time taken is 1.5 hours. Therefore, the distance traveled by the motorboat from port B to port A is:

Distance_BA = (2x) × 1.5

# Total Distance Traveled

The total distance traveled by the boat and the motorboat is the sum of the distances traveled in each direction:

Total Distance = Distance_AB + Distance_BA

# Relationship between Distance and Speed

The relationship between distance, speed, and time is given by the formula:

Distance = Speed × Time

Using this formula, we can rewrite the equation for the total distance as:

Total Distance = (x × 1.5) + ((2x) × 1.5)

Simplifying the equation, we get:

Total Distance = 1.5x + 3x

# Relationship between Speed and Time

We are given that the speed of the river is 4 km/h. The speed of the boat is the sum of the speed of the river and the speed of the boat relative to the river. Therefore, we can write the equation:

Speed_boat = Speed_river + Speed_relative

The speed of the boat is x km/h, and the speed of the river is 4 km/h. Therefore, the equation becomes:

x = 4 + Speed_relative

# Relationship between Speed and Distance

The relationship between speed, distance, and time is given by the formula:

Speed = Distance / Time

Using this formula, we can rewrite the equation for the boat's journey from port A to port B as:

x = Distance_AB / 1.5

Substituting the value of Distance_AB, we get:

x = (x × 1.5) / 1.5

Simplifying the equation, we get:

x = x

# Solving the Equations

We have two equations:

1. Total Distance = 1.5x + 3x 2. x = 4 + Speed_relative

We can solve these equations simultaneously to find the values of x and Speed_relative.

Simplifying equation 1, we get:

Total Distance = 4.5x

Substituting the value of Total Distance from equation 1 into equation 2, we get:

4.5x = 4 + Speed_relative

Simplifying the equation, we get:

Speed_relative = 4.5x - 4

Now, we can substitute the value of Speed_relative into equation 2 to find the value of x:

x = 4 + (4.5x - 4)

Simplifying the equation, we get:

x = 4 + 4.5x - 4

Simplifying further, we get:

x = 0.5x

Dividing both sides of the equation by 0.5, we get:

x / 0.5 = x

Simplifying the equation, we get:

2x = x

Therefore, x = 0.

Answer

The speed of the boat is 0 km/h. However, this result seems unlikely and may indicate an error in the problem statement or calculations. Please double-check the problem and calculations to ensure accuracy.

Note: The solution provided is based on the information given in the problem statement. If there are any additional details or constraints, please provide them for a more accurate solution.