Question

Решите задачу: Через первую трубу бак наполняется за 25 мин. ,а через вторую за 40 мин. Наполнится ли за бак за 15 мин. если открыть обе трубы? СКОРЕЕ,МНЕ СРОЧНО!!!!! ДАЮ 80 БАЛЛОВ!!!!!!!!!

Answer 1

Скорость наполнения первой трубой 1/25 б/мин
скорость наполнения второй 1/40 б/мин
через две трубы в минуту вольется
1/25+1/40=(40+25)/1000=65/1000=13/200 б/мин
за 15 мин
13*15/200=195/200 бака=0,975=97,5% бака
ответ не успеет.

Answer 2

за 15 минут не наполнится
за одну минуту первая труба наполнит 1\25 часть бака 
за одну минуту вторая труба наполнит 1\40 часть бака 
обе трубы за одну минуту наполнят 1\25+1\40=13\200 часть бака 
весь бак будет наполнен за 1:13\200 = 15 5\13минут 

Answer 3

Problem Analysis

We are given that the first pipe can fill a tank in 25 minutes, and the second pipe can fill the same tank in 40 minutes. We need to determine if the tank will be filled in 15 minutes if both pipes are opened simultaneously.

Solution

To solve this problem, we need to calculate the rate at which each pipe fills the tank. We can then add the rates of both pipes to find the combined rate at which the tank is being filled. Finally, we can use the combined rate to determine if the tank will be filled in 15 minutes.

Let's calculate the rates of each pipe first:

- The first pipe fills the tank in 25 minutes, so its filling rate is 1/25 of the tank per minute. - The second pipe fills the tank in 40 minutes, so its filling rate is 1/40 of the tank per minute.

To find the combined rate, we add the rates of both pipes:

1/25 + 1/40 = (40 + 25) / (25 * 40) = 65 / 1000

The combined rate is 65/1000 of the tank per minute.

Now, let's determine if the tank will be filled in 15 minutes. We can multiply the combined rate by 15 and check if it equals 1 (which would mean the tank is completely filled):

(65/1000) * 15 = 975/1000

Since 975/1000 is less than 1, the tank will not be completely filled in 15 minutes if both pipes are opened simultaneously.

Therefore, the answer to the problem is no, the tank will not be filled in 15 minutes if both pipes are opened simultaneously.

Conclusion

If both pipes are opened simultaneously, the tank will not be completely filled in 15 minutes. The combined rate of the two pipes is not sufficient to fill the tank in that time frame.