Question

8. Первый рабочий выполняет работу за 10 дней, второй - за 12 дней, третий - за 15 дней. Первыйи второй рабочие работали 3 дня, а остальнуючасть работы продолжили второй и третийЕ рабочие. За сколько дней выполнилась работа?​

Answer 1

Ответ:

6

Пошаговое объяснение

$3*(\frac{1}{10} +\frac{1}{12} )=3*\frac{11}{60} =\frac{11}{20} \\1-\frac{11}{20}=\frac{9}{20}\\(\frac{1}{12} +\frac{1}{15} )x=\frac{9}{20}\\\\ \frac{9x}{60} =\frac{9}{20} \\x=3$  3 дня работали вместе 2й  и 3й рабочий

работа закончено  в течении 3+3=6 дней

Answer 2

Problem Analysis

We are given that three workers are completing a job. The first worker can complete the job in 10 days, the second worker can complete it in 12 days, and the third worker can complete it in 15 days. The first and second workers worked for 3 days, and then the second and third workers completed the remaining work. We need to determine how many days it took to complete the entire job.

Solution

To solve this problem, we can calculate the work rate of each worker and then use the work rate to determine the total time required to complete the job.

Let's assume that the total work required to complete the job is 1 unit.

The first worker can complete the job in 10 days, so their work rate is 1/10 units per day.

The second worker can complete the job in 12 days, so their work rate is 1/12 units per day.

The third worker can complete the job in 15 days, so their work rate is 1/15 units per day.

The first and second workers worked for 3 days, so they completed a total of (1/10 + 1/12) * 3 = 11/20 units of work.

The remaining work is (1 - 11/20) = 9/20 units.

The second and third workers completed the remaining work, so their combined work rate is (1/12 + 1/15) = 9/60 + 12/60 = 21/60 units per day.

To find the number of days required to complete the remaining work, we can use the formula:

Time = Work / Rate

Substituting the values, we get:

Time = (9/20) / (21/60) = (9/20) * (60/21) = 27/7 ≈ 3.857 days.

Therefore, the entire job was completed in approximately 3.857 days.

Answer

The job was completed in approximately 3.857 days.

Note: The answer has been calculated based on the given information and the assumption that the total work required to complete the job is 1 unit.