Question

Бак наполнится водой через две трубы за 2ч.через первую трубу бак может наполнится за 3ч.за сколько времени 2/3 объёма бака наполнятся водой через вторую трубу?

Answer 1

1)2*3=6(ч)-скорость 2 трубы
2)2/3:6=4(ч)
Ответ:4 часа 

Answer 2

Problem Analysis

We have a tank that can be filled with water through two pipes. The tank can be filled in 2 hours using both pipes, and it can be filled in 3 hours using the first pipe alone. We need to determine how long it will take to fill 2/3 of the tank using the second pipe alone.

Solution

Let's assume that the capacity of the tank is represented by C. We are given the following information: - The tank can be filled in 2 hours using both pipes. - The tank can be filled in 3 hours using the first pipe alone.

To find the time it takes to fill 2/3 of the tank using the second pipe alone, we can use the concept of work. The work done to fill the tank completely is equal to its capacity, which is C.

Let's calculate the work done by each pipe in 1 hour: - Both pipes together can fill the tank in 2 hours, so the work done by both pipes in 1 hour is C/2. - The first pipe alone can fill the tank in 3 hours, so the work done by the first pipe in 1 hour is C/3.

Now, let's calculate the time it takes to fill 2/3 of the tank using the second pipe alone. We know that the work done by both pipes in 1 hour is C/2. Therefore, the work done by the second pipe alone in 1 hour is C/2 - C/3 = C/6.

To find the time it takes to fill 2/3 of the tank using the second pipe alone, we can set up the following equation:

Time taken = (Work to be done) / (Work done per hour)

The work to be done is 2/3 of the tank's capacity, which is (2/3)C. The work done per hour by the second pipe is C/6.

Substituting these values into the equation, we get:

Time taken = (2/3)C / (C/6) = (2/3) * 6 = 4 hours

Therefore, it will take 4 hours to fill 2/3 of the tank using the second pipe alone.

Answer

It will take 4 hours to fill 2/3 of the tank with water using the second pipe alone.