Question

Боря купил 4 книги. Все книги без первой стоят 42 рубля ,без второй - 40 рублей , без третей 38 рублей , без четвёртой 36 рублей . Сколько стоит каждая книга .

Answer 1

10 рублей,12 рублей,14 рублей, 16 рублей 

Answer 2

10рублей,12рублей,14рублей и 16 рублей

Answer 3

Calculating the Cost of Each Book

To calculate the cost of each book, we can use the given information about the prices of the books without the first, second, third, and fourth books.

Let's denote the cost of the first book as x.

The cost of the second book would be x + 2 (42 - 40 = 2).

The cost of the third book would be x + 4 (42 - 38 = 4).

The cost of the fourth book would be x + 6 (42 - 36 = 6).

By solving these equations, we can find the value of x and then calculate the cost of each book.

Calculation

Using the given information, we can set up the following equations:

1. x + 2 = 40 2. x + 4 = 38 3. x + 6 = 36

Solving these equations:

1. x = 40 - 2 = 38 2. x = 38 - 4 = 34 3. x = 36 - 6 = 30

So, the cost of each book is: - The first book costs 38 rubles - The second book costs 40 rubles - The third book costs 38 rubles - The fourth book costs 36 rubles

This calculation is based on the given information and the equations derived from it.