Question

Кран с холодной водой заполняет ванну за 19 минут, а с горячей за 23 минуты.Открыли кран с горячей водой.Через сколько минут нужно открыть кран с холодной водой, чтобы к тому моменту, как ванна будет заполнена полностью, в ней холодной и горячей воды было поровну?

Answer 1

23=100%
x=50%
x=23×50/100=11.5

9=100%
y=50%
y=9×50/100=4.5

11.5-4.5=7 ответ через 7 минут

Answer 2

Problem Analysis

To solve this problem, we need to determine the timing for opening the cold water tap after the hot water tap has been opened, so that the bathtub is filled with an equal amount of hot and cold water when it is completely filled.

Solution

The key to solving this problem is to find the time at which the hot water tap has been running for the same duration as the cold water tap will need to run to fill the bathtub.

1. Calculate the time for the hot water tap to run: - The hot water tap fills the bathtub in 23 minutes.

2. Determine the time to open the cold water tap: - To ensure an equal amount of hot and cold water in the bathtub, the cold water tap should be opened when the hot water tap has been running for 19 minutes, as it takes 19 minutes for the cold water tap to fill the bathtub.

3. Calculate the time to open the cold water tap after the hot water tap: - The difference in time between the hot water tap and the cold water tap is 23 - 19 = 4 minutes.

Conclusion

To ensure that the bathtub is filled with an equal amount of hot and cold water when it is completely filled, the cold water tap should be opened 4 minutes after the hot water tap has been opened.