Question

Чтобы выкачать воду из резервуара, ставят насос, выкачивающий 30 лит. в минуту; через 50 мин. берут другой насос, выкачивающий 70 лит. в минуту,и насосы работают вместе 45 минут.За какое время могла бы быть выкачана вода,если бы с самого начала работали оба насоса вместе?

Answer 1

1)30•50=1500л
2)70•45=3150л
3)1500+3150=4650л

Answer 2

Problem Analysis

To solve this problem, we need to determine the time it would take to pump out the water from the reservoir if both pumps were working together from the beginning.

Given Information

- Pump 1 can pump out 30 liters of water per minute. - Pump 2 can pump out 70 liters of water per minute. - Pump 1 is used for the first 50 minutes. - Pump 2 is used for the next 45 minutes. - We need to find the total time it would take to pump out the water if both pumps were used together from the beginning.

Solution

Let's calculate the amount of water pumped out by each pump individually and then determine the total time it would take if both pumps were used together.

1. Pump 1: - Pump 1 works for 50 minutes and pumps out 30 liters of water per minute. - Therefore, the total amount of water pumped out by Pump 1 is 50 minutes * 30 liters/minute = 1500 liters.

2. Pump 2: - Pump 2 works for 45 minutes and pumps out 70 liters of water per minute. - Therefore, the total amount of water pumped out by Pump 2 is 45 minutes * 70 liters/minute = 3150 liters.

3. Both Pumps Together: - If both pumps were used together from the beginning, they would work for a total of 95 minutes (50 minutes for Pump 1 + 45 minutes for Pump 2). - The combined pumping rate of both pumps is 30 liters/minute + 70 liters/minute = 100 liters/minute. - Therefore, the total amount of water pumped out by both pumps working together is 95 minutes * 100 liters/minute = 9500 liters.

Answer

If both pumps were used together from the beginning, it would take a total of 95 minutes to pump out the water from the reservoir.