Question

Ученик купил по одинаковой цене 9 тетрадей в линейку и 5 тетрадей в клетку. За тетради в линейку он заплатил на 12 р. больше. Сколько стоили тетради в линейку? Сколько стоили тетради в клету?

Answer 1

1)9-5=4(тетради стоят 12 рублей)2)12:4=3 (руб.)стоит 1 тетрадь.   3)9*3=27(руб)тетради в линейку4)5*3=15 (руб.) тетради в клетку.

Answer 2

Problem Analysis

The student bought 9 notebooks in a line and 5 notebooks in a grid. The notebooks in the line cost 12 rubles more than the notebooks in the grid. We need to find the cost of the notebooks in the line and the cost of the notebooks in the grid.

Solution

Let's assume the cost of the notebooks in the line is x rubles and the cost of the notebooks in the grid is y rubles.

According to the given information, the student bought 9 notebooks in a line and 5 notebooks in a grid. The total cost of the notebooks in the line is 12 rubles more than the total cost of the notebooks in the grid.

We can set up the following equations based on the given information:

Equation 1: 9x = 5y + 12

We can solve this equation to find the values of x and y.

Solving the Equation

To solve the equation, we can rearrange it to isolate one variable:

9x - 5y = 12

Now, let's solve the equation using the substitution method.

We can express x in terms of y:

x = (5y + 12) / 9

Substituting this value of x into Equation 1:

9 * ((5y + 12) / 9) - 5y = 12

Simplifying the equation:

5y + 12 - 5y = 12

The y terms cancel out, leaving us with:

12 = 12

This equation is true for any value of y. Therefore, there are infinitely many possible solutions for the cost of the notebooks in the line and the cost of the notebooks in the grid.

We cannot determine the specific values of x and y without additional information.

Conclusion

Based on the given information, we cannot determine the specific cost of the notebooks in the line and the cost of the notebooks in the grid. There are infinitely many possible solutions for these values.