Question

Три лесопосадочные машины могут посадить за один день столько же деревьев, сколько 40 человек ручным способом. Колхоз предполагал произвести посадку леса силами 15 человек в течение 8 дней. За какое время закончат эту работу две лесопосадочные машины?

Answer 1

40 чел. выполнять 100%
15 чел. = 37,5% в день

3 маш. = 100%
2 маш. = 66,67%

37,5 * 8=300  посадка леса силами   15 человек в течение 8 дней.
300 : 66,67 = 4,5 за такое время закончат эту работу две лесопосадочные машины

Answer 2

Calculation of Tree Planting Efficiency

To determine the time it would take for two tree planting machines to complete the task, we need to compare their efficiency with that of manual labor.

According to the given information, three tree planting machines can plant as many trees in one day as 40 people can plant manually. Additionally, the collective effort of 15 people is expected to complete the task in 8 days.

Let's calculate the number of trees planted by 40 people in one day:

40 people = 3 tree planting machines 1 day = 3 tree planting machines

Therefore, the number of trees planted by 40 people in one day is equal to the number of trees planted by three tree planting machines in one day.

Now, let's calculate the number of trees planted by 15 people in 8 days:

15 people = x tree planting machines 8 days = x tree planting machines

To find the value of x, we can set up a proportion:

40 people / 1 day = 15 people / 8 days

Cross-multiplying, we get:

40 people * 8 days = 15 people * 1 day

320 people-days = 15 people-days

Dividing both sides by 15 people-days, we find:

320 / 15 = x

x ≈ 21.33

Therefore, it would take approximately 21.33 tree planting machines to complete the task in 8 days.

Since we have two tree planting machines, we can calculate the time it would take for them to finish the job:

15 people = 2 tree planting machines x days = 2 tree planting machines

Using the same proportion method as before:

40 people / 1 day = 15 people / x days

Cross-multiplying, we get:

40 people * x days = 15 people * 1 day

40x = 15

Dividing both sides by 40, we find:

x ≈ 0.375

Therefore, it would take approximately 0.375 days, or about 9 hours, for two tree planting machines to complete the task.

Please note that these calculations are based on the given information and assumptions.