Question

Три книги и 5 тетрадей стоят 7 манат, 1 книга и 2 тетради стоят 2,45 манат.1)Сколько стоят вместе 1 книга и 1 тетрадь

Answer 1

Calculating the Cost of Books and Notebooks

To find the cost of 1 book and 1 notebook, we can use the given information about the cost of 3 books and 5 notebooks, as well as the cost of 1 book and 2 notebooks.

Let's denote the cost of 1 book as b and the cost of 1 notebook as n.

From the given information: 1. 3 books and 5 notebooks cost 7 manat. 2. 1 book and 2 notebooks cost 2.45 manat.

We can set up the following system of equations to solve for b and n: ``` 3b + 5n = 7 b + 2n = 2.45 ```

Solving the System of Equations

To solve the system of equations, we can use various methods such as substitution or elimination. Let's use the substitution method to find the values of b and n.

From the second equation, we can express b in terms of n: ``` b = 2.45 - 2n ``` Now, we can substitute this expression for b into the first equation: ``` 3(2.45 - 2n) + 5n = 7 7.35 - 6n + 5n = 7 7.35 - n = 7 -n = 7 - 7.35 -n = -0.35 n = 0.35 ``` Now that we have found the value of n, we can substitute it back to find the value of b: ``` b = 2.45 - 2(0.35) b = 2.45 - 0.7 b = 1.75 ```

Calculating the Cost of 1 Book and 1 Notebook

Now that we have the values of b and n, we can calculate the cost of 1 book and 1 notebook: ``` 1 book + 1 notebook = 1.75 + 0.35 = 2.10 manat ```

So, the cost of 1 book and 1 notebook together is 2.10 manat.