Question

задача строительная бригада построила 18 двухэтажных и трёхэтажных домов. на их строительство понадобилось 140 плит.известно, что на один двухэтажный дом ушло 6 плит,а на один трёхэтажный дом - на 4 плиты больше. сколько двухэтажных домов построила бригада?

Answer 1

Problem Analysis

We are given that a construction crew built 18 two-story and three-story houses, and it took 140 slabs to build them. We also know that it took 6 slabs to build one two-story house and that one three-story house required 4 more slabs than a two-story house.

We need to determine how many two-story houses the crew built.

Solution

Let's assume the number of two-story houses built is x. Since the crew built a total of 18 houses, the number of three-story houses built would be 18 - x.

We know that it took 6 slabs to build one two-story house and that one three-story house required 4 more slabs than a two-story house. Therefore, the total number of slabs used can be calculated as follows:

Total slabs = (number of two-story houses * 6) + (number of three-story houses * (6 + 4))

We also know that the total number of slabs used is 140. So, we can set up the following equation:

(x * 6) + ((18 - x) * (6 + 4)) = 140

Now, let's solve this equation to find the value of x.

Calculation

Expanding the equation, we get:

6x + (18 - x) * 10 = 140

Simplifying further:

6x + 180 - 10x = 140

Combining like terms:

-4x + 180 = 140

Subtracting 180 from both sides:

-4x = -40

Dividing both sides by -4:

x = 10

Answer

The construction crew built 10 two-story houses.

Explanation

By solving the equation, we found that the number of two-story houses built by the construction crew is 10. This means that they built 10 two-story houses and 8 three-story houses.