Question

Один насос может наполнить басейн за 3часов, а второй за4часов. За какое время наполнят бассейн оба насоса, если их включить одновременно?

Answer 1

3+4=7(ч)-общее время

Answer 2

может так 3+4=7
7-1=6

Answer 3

Problem Analysis

We are given two pumps, one of which can fill a pool in 3 hours and the other in 4 hours. We need to determine how long it will take to fill the pool if both pumps are turned on simultaneously.

Solution

To solve this problem, we can calculate the rate at which each pump fills the pool and then add their rates together to find the combined rate. We can then use the combined rate to determine how long it will take to fill the pool.

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

The first pump can fill the pool in 3 hours, which means it fills 1/3 of the pool's capacity per hour. Similarly, the second pump can fill the pool in 4 hours, so it fills 1/4 of the pool's capacity per hour.

If both pumps are turned on simultaneously, their combined rate will be the sum of their individual rates. Therefore, the combined rate is (1/3 + 1/4) of the pool's capacity per hour.

To find the time it takes to fill the pool with both pumps running, we can divide the pool's capacity (1 unit) by the combined rate. This will give us the time in hours.

Let's calculate it:

1. Calculate the combined rate: - The first pump fills 1/3 of the pool's capacity per hour. - The second pump fills 1/4 of the pool's capacity per hour. - The combined rate is (1/3 + 1/4) = 7/12 of the pool's capacity per hour.

2. Calculate the time it takes to fill the pool: - Divide the pool's capacity (1 unit) by the combined rate (7/12 units per hour). - The time it takes to fill the pool is (1 / (7/12)) = 12/7 hours.

Therefore, if both pumps are turned on simultaneously, it will take 12/7 hours to fill the pool.

Answer

If both pumps are turned on simultaneously, it will take 12/7 hours to fill the pool.

Source:

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