Question

Помогите!Первая бригада рабочих может построить дом за 24 дня.Время,за которое может построить этот дом вторая бригада,составляет 75%от времени,необходимого для этого первой бригаде.Сколько процентов всех строительных работ будет незавершенными после 9 дней совместной работы двух бригад.

Answer 1

24*3/4=18(дн)-2 бригада
(18+24):2=18/2+24/2=9+12=21(д)-совместная работа
21-9=12(дн)-осталось
12-x
21-100%
12*100=21x
-21x=-1200:(-21)
x=1200/21=57 3/21=57 1/7(%)

Answer 2

Problem Analysis

We are given that the first team of workers can build a house in 24 days. The second team can build the same house in 75% of the time it takes the first team. We need to determine the percentage of the total construction work that will be unfinished after 9 days of joint work by both teams.

Solution

Let's start by calculating the time it takes for the second team to build the house. We know that the second team can build the house in 75% of the time it takes the first team. Therefore, the time taken by the second team is 75% of 24 days, which is 18 days.

Now, we need to find the percentage of the total construction work that will be unfinished after 9 days of joint work by both teams. To do this, we need to calculate the fraction of the work completed by both teams in 9 days.

The first team can complete 1/24th of the work in one day, so in 9 days, they can complete 9/24th of the work.

The second team can complete 1/18th of the work in one day, so in 9 days, they can complete 9/18th of the work.

To find the total work completed by both teams in 9 days, we add the fractions:

9/24 + 9/18 = (9 * 3 + 9 * 2) / (24 * 3) = 45/72 = 5/8

Therefore, after 9 days of joint work by both teams, 5/8th of the work will be completed.

To find the percentage of the work unfinished, we subtract the fraction of work completed from 1 and multiply by 100:

(1 - 5/8) * 100 = 3/8 * 100 = 37.5%

Therefore, 37.5% of all construction work will be unfinished after 9 days of joint work by both teams.

Answer

After 9 days of joint work by both teams, 37.5% of all construction work will be unfinished.