Question

Бассейн через 1 трубу наполняется за 14 часов. А через 2 трубу вытекает за 8 часов. Однажды 2ю трубу забыли закрыть. За сколько времени наполнится бассейн?

Answer 1

1)1:20=1/20 часть наполняет первая труба за 1 час

2)1:30=1/30 часть наполняет вторая труба за 1 час

3)1/20+1/30=1/12 часть заполняют обе трубы за 1 час

4)1:1/12=12 часов

Answer 2

Problem Analysis

We have a pool that can be filled through one pipe in 14 hours and emptied through another pipe in 8 hours. However, one day we forgot to close the second pipe. We need to determine how long it will take to fill the pool under these conditions.

Solution

To solve this problem, we need to consider the rates at which the pool is filled and emptied.

Let's assume that the capacity of the pool is 1 unit (this could be any unit of measurement, such as liters or gallons).

The rate at which the pool is filled through one pipe is 1/14 units per hour. This means that in one hour, 1/14th of the pool's capacity is filled.

The rate at which the pool is emptied through the second pipe is 1/8 units per hour. This means that in one hour, 1/8th of the pool's capacity is emptied.

When both pipes are open, the net rate at which the pool is filled is the difference between the filling rate and the emptying rate. So, the net rate is 1/14 - 1/8 units per hour.

To find out how long it will take to fill the pool, we need to divide the pool's capacity by the net filling rate.

Let's calculate the time it will take to fill the pool:

1. The net filling rate is 1/14 - 1/8 units per hour. 2. The time it will take to fill the pool is 1 / (1/14 - 1/8) hours.

Now, let's calculate the time:

1 / (1/14 - 1/8) = 1 / (2/56 - 7/56) = 1 / (-5/56) = -56/5 = -11.2 hours

The negative value indicates that the pool cannot be filled under these conditions. This means that the pool will never be filled if both pipes are open.

Conclusion

If the second pipe is left open, the pool will never be filled.