Question

игорь и паша красят забор за 12 часов .паша и володя красят этот же забор за 15 часов,а володя и игорь за 20 часов .за сколько часов мальчики красят забор ,работая втроем

Answer 1

Работу берем за 1 и приравниваем к 60.
И+П=1/15=4/60
И+В=1/12=5/60
В+П=1/20=3/60
Вместе 12/60=1/5
1:1/5=5 часов
5*2=10 (т.к каждый участв.2 раза)
Ответ:10

Answer 2

Calculating the Time Taken to Paint the Fence

To calculate the time taken for Igor, Pasha, and Volodya to paint the fence together, we can use the formula:

1 / (time taken by Igor) + 1 / (time taken by Pasha) + 1 / (time taken by Volodya) = 1 / (time taken together)

Let's calculate the time taken for the three boys to paint the fence together.

Using the given information: - Igor and Pasha paint the fence in 12 hours. - Pasha and Volodya paint the same fence in 15 hours. - Volodya and Igor paint the fence in 20 hours.

We can use the formula to calculate the time taken for the three boys to paint the fence together.

1 / 12 + 1 / 15 + 1 / 20 = 1 / (time taken together)

Calculating the time taken together: ``` 1 / 12 + 1 / 15 + 1 / 20 = 0.0833 + 0.0667 + 0.05 = 0.2 1 / (time taken together) = 0.2 (time taken together) = 1 / 0.2 (time taken together) = 5 hours ```

Answer

Therefore, the three boys will paint the fence together in 5 hours.