Question

Две книги стоят вместе 34 евро. После того, как первую книгу уценили на 10%, а вторую уценили на 30%, общая стоимость этих книг составила 26 евро 32 цента. найди первоначальные стоимости книг

Answer 1

Пусть х стоила первая книга, тогда вторая стоила у.
х+у=34
х0,9+у0,7=26,32
Выделяем х в первом уравнении:
х=34-у
Подставляем значение х во второе уравнение:
0,9(34-у)+0,7у=26,32
30,6-0,2у=26,32
0,2у=4,28
у=21,4 € стоит вторая книга.
34-21,4=12,6 € стоит первая книга.
Ответ: 12,6 € первая, 21,4 € вторая.

Answer 2

Problem Analysis

We are given that two books together cost 34 euros. After the first book is discounted by 10% and the second book is discounted by 30%, the total cost of the books becomes 26 euros and 32 cents. We need to find the original prices of the books.

Solution

Let's assume the original price of the first book is x euros and the original price of the second book is y euros.

According to the given information, we can set up the following equations:

Equation 1: x + y = 34 (since the two books together cost 34 euros) Equation 2: 0.9x + 0.7y = 26.32 (after the discounts are applied)

To solve this system of equations, we can use substitution or elimination method. Let's use the substitution method.

From Equation 1, we can express x in terms of y: x = 34 - y

Substituting this value of x in Equation 2, we get: 0.9(34 - y) + 0.7y = 26.32

Simplifying the equation: 30.6 - 0.9y + 0.7y = 26.32 30.6 - 0.2y = 26.32 -0.2y = 26.32 - 30.6 -0.2y = -4.28 y = -4.28 / -0.2 y = 21.4

Now, substituting the value of y back into Equation 1, we can find the value of x: x = 34 - y x = 34 - 21.4 x = 12.6

Therefore, the original price of the first book was 12.6 euros and the original price of the second book was 21.4 euros.

Answer

The original price of the first book was 12.6 euros and the original price of the second book was 21.4 euros.