Question

Две бригады штукатуров отделывали дом. Первая бригада, работая одна, может выполнить всю работу за 6 дней, а вторая за 12 дней. Первая бригада работала 3 дня а затем вторая закончила работу. За сколько дней бригады закончили отделку дома? Сад прямоугольной формы хотят обнести забором. Длина сада 800м, а ширина состовляет четверть длины. Какой длины должен быть весь забор?

Answer 1

1) 1я бригада отработала 3 дня - это половина всей работы (т.к. 6 дней на всю работу ей нужно). Значит 1я бригада отработала вторую половину работы за 12/2=6 дней. Итого: 3+6=9дней

2) ширина сада 800/4=200м. Общая длина забора - 800*2+200*2 = 2000 метров

Answer 2

Question 1: Две бригады штукатуров отделывали дом. Первая бригада, работая одна, может выполнить всю работу за 6 дней, а вторая за 12 дней. Первая бригада работала 3 дня, а затем вторая закончила работу. За сколько дней бригады закончили отделку дома?

To find out how many days it took for both brigades to finish the house, we need to calculate the combined work rate of the two brigades.

Let's assume that the work rate of the first brigade is represented by x (in terms of the fraction of work completed per day), and the work rate of the second brigade is represented by y (also in terms of the fraction of work completed per day).

According to the given information, the first brigade can complete the entire job in 6 days when working alone, and the second brigade can complete the entire job in 12 days when working alone.

From this, we can set up the following equations:

- The work rate of the first brigade: x = 1/6 - The work rate of the second brigade: y = 1/12

Now, let's calculate the total work done by each brigade:

- The work done by the first brigade in 3 days: 3 * x = 3/6 = 1/2 - The work done by the second brigade in the remaining days: (12 - 3) * y = 9 * y

To find the total work done by both brigades, we add the work done by each brigade:

1/2 + 9y

Since the total work done by both brigades is equal to 1 (the entire job), we can set up the equation:

1/2 + 9y = 1

Now, let's solve for y:

9y = 1 - 1/2 = 1/2

y = 1/2 / 9 = 1/18

Therefore, the work rate of the second brigade is 1/18.

To find out how many days it took for both brigades to finish the house, we can calculate the total work done in one day by adding the work rates of both brigades:

x + y = 1/6 + 1/18 = 4/18 + 1/18 = 5/18

To find the number of days it took for both brigades to finish the house, we can calculate the reciprocal of the combined work rate:

18/5 = 3.6 days

Therefore, it took both brigades approximately 3.6 days to finish the house.

Question 2: Сад прямоугольной формы хотят обнести забором. Длина сада 800м, а ширина составляет четверть длины. Какой длины должен быть весь забор?

To find the length of the entire fence needed to enclose the rectangular garden, we need to calculate the perimeter of the garden.

Given that the length of the garden is 800m and the width is one-fourth of the length, we can calculate the width as follows:

Width = Length / 4 = 800m / 4 = 200m

Now, let's calculate the perimeter of the garden:

Perimeter = 2 * (Length + Width) = 2 * (800m + 200m) = 2 * 1000m = 2000m

Therefore, the length of the entire fence needed to enclose the garden should be 2000m.