Question

На первой полке книг в 2 раза меньше, чем на второй, и на 3 книги больше, чем на третьей. Сколько книг стоит на каждой полке, если на трёх полках всего 77 книг?

Answer 1

Пусть х книг на первой полке, тогда 2х книг на второй и х - 3 на третьей. На трёх полках всего 77 книг. Уравнение:

х + 2х + х - 3 = 77

4х = 77 + 3

4х = 80

х = 80 : 4

х = 20 книг - на первой полке

2 · 20 = 40 книг - на второй полке

20 - 3 = 17 книг - на третьей полке

Ответ: 20, 40 и 17 книг.

Answer 2

Problem Analysis

We are given the following information: - The number of books on the first shelf is twice as less as the number of books on the second shelf. - The number of books on the third shelf is three more than the number of books on the second shelf. - The total number of books on all three shelves is 77.

We need to determine the number of books on each shelf.

Solution

Let's assume the number of books on the second shelf is x.

According to the given information: - The number of books on the first shelf is twice as less as the number of books on the second shelf, which means it is x/2. - The number of books on the third shelf is three more than the number of books on the second shelf, which means it is x + 3.

The total number of books on all three shelves is 77, so we can write the equation: x/2 + x + (x + 3) = 77.

Simplifying the equation: x/2 + x + x + 3 = 77, 5x/2 + 3 = 77, 5x/2 = 74, 5x = 148, x = 148/5, x = 29.6.

Since the number of books cannot be a decimal, we can round down the value of x to the nearest whole number, which is 29.

Therefore, the number of books on each shelf is as follows: - First shelf: x/2 = 29/2 = 14.5 (rounded down to 14). - Second shelf: x = 29. - Third shelf: x + 3 = 29 + 3 = 32.

So, there are 14 books on the first shelf, 29 books on the second shelf, and 32 books on the third shelf.

Answer

There are 14 books on the first shelf, 29 books on the second shelf, and 32 books on the third shelf.