Question

В одной тетради и одном блокноте вместе 30 страниц. В двух блокнотах столько же страниц, сколько их в трех тетрадях. Сколько страниц в каждой тетради и в каждом блокноте?

Answer 1

Ответ:

x=12(в тетради),y=18(в блокноте)

Пошаговое объяснение:

$\left \{ {{x+y=30} \atop {2y=3x}} \right.$

$\left \{ {{x=30-y} \atop {2y=3(30-y)}} \right.$

2y=90-3y

5y=90

y=18

x=30-18

x=12

Answer 2

Problem Analysis

We are given the following information: - There are 30 pages in one notebook and one notepad combined. - There are the same number of pages in two notepads as there are in three notebooks.

We need to find the number of pages in each notebook and each notepad.

Solution

Let's assume the number of pages in each notebook is x and the number of pages in each notepad is y.

From the given information, we can form the following equations:

Equation 1: The total number of pages in one notebook and one notepad combined is 30. ``` x + y = 30 ```

Equation 2: The total number of pages in two notepads is the same as the total number of pages in three notebooks. ``` 2y = 3x ```

To solve these equations, we can use substitution or elimination method.

Substitution Method

We can solve Equation 1 for x and substitute it into Equation 2.

From Equation 1, we have: ``` x = 30 - y ```

Substituting this value of x into Equation 2, we get: ``` 2y = 3(30 - y) 2y = 90 - 3y 5y = 90 y = 18 ```

Now, substituting the value of y back into Equation 1, we can find x: ``` x = 30 - 18 x = 12 ```

Therefore, there are 12 pages in each notebook and 18 pages in each notepad.

Answer

There are 12 pages in each notebook and 18 pages in each notepad.