Question

Игорь и паша красят забор за 5 часов паша и володя красят тот же забор за 6 часов. Игорь и володя красят забор за 20 часов. за сколько они в 3 покрасят заборНужен только ответ. в минутах

Answer 1

В часах выходит 4 часа и 4/5 часа. В четырех часах 240 минут. Если перевести 4/5 часа в минуты, получим 48 минут, сложим 240 +48= 288 минут

Answer 2

Problem Analysis

Игорь и Паша красят забор за 5 часов, Паша и Володя красят тот же забор за 6 часов, Игорь и Володя красят забор за 20 часов. Нужно определить, за сколько они втроем покрасят забор.

Solution

To solve this problem, we can use the concept of work rates. The work rate is defined as the amount of work done per unit of time. If we assume that the amount of work required to paint the fence is the same, we can set up the following equations:

Let's assume that the work required to paint the fence is 1 unit.

- Igor and Pasha can paint the fence in 5 hours, so their work rate is 1/5 units per hour. - Pasha and Volodya can paint the fence in 6 hours, so their work rate is 1/6 units per hour. - Igor and Volodya can paint the fence in 20 hours, so their work rate is 1/20 units per hour.

To find the work rate when all three of them work together, we can add up their individual work rates:

Work rate of Igor and Pasha: 1/5 units per hour Work rate of Pasha and Volodya: 1/6 units per hour Work rate of Igor and Volodya: 1/20 units per hour

Adding these work rates together, we get:

(1/5) + (1/6) + (1/20) = (4/20) + (3/20) + (1/20) = 8/20 = 2/5 units per hour

This means that when all three of them work together, their combined work rate is 2/5 units per hour. To find the time it takes for them to paint the fence, we can use the formula:

Time = Work / Work rate

Since the work required to paint the fence is 1 unit, we can substitute the values into the formula:

Time = 1 / (2/5) = 5/2 = 2.5 hours

Therefore, it will take them 2.5 hours to paint the fence together.

Answer

Они втроем покрасят забор за 2.5 часа.