Question

Два землекопа за два часа выкопали канаву длиной 2метра.сколько землекопов за 5часов выкопают канаву длиной 5метра.

Answer 1

Один землекоп за час выкопает 2 / 2 / 2 = 1/2 м.
Один землекоп за 5 часов выкопает 1/2 * 5 = 5/2 м.
Значит, нам нужно 2 землекопа. вот так !

Answer 2

Problem Analysis

We are given that two excavators can dig a trench of 2 meters in 2 hours. We need to determine how many excavators are needed to dig a trench of 5 meters in 5 hours.

Solution

To solve this problem, we can use the concept of work rate. The work rate is the amount of work done per unit of time. In this case, the work rate is the length of the trench dug per hour.

Let's calculate the work rate of the two excavators: - Two excavators can dig a trench of 2 meters in 2 hours. - Therefore, the work rate of the two excavators is 2 meters / 2 hours = 1 meter per hour.

Now, let's calculate the number of excavators needed to dig a trench of 5 meters in 5 hours: - We know that the work rate of two excavators is 1 meter per hour. - To dig a trench of 5 meters in 5 hours, we need a work rate of 5 meters / 5 hours = 1 meter per hour.

Since the work rate required is the same as the work rate of the two excavators, we can conclude that two excavators are still needed to dig a trench of 5 meters in 5 hours.

Conclusion

Two excavators are needed to dig a trench of 5 meters in 5 hours, just like in the initial scenario where they dug a trench of 2 meters in 2 hours.

Please let me know if you need any further assistance!