Question

Задача: На трёх полках в библиотеки 90 книг. На первой полке 45 книг,а на второй полке на 18 книг - меньше чем на первой . На сколько меньше книг на третьей полке чем на первой . ПОМОГИТЕ ПОЖАЛУЙСТА

Answer 1

1)45-18=27 книг на второй полке
2)45+27=72 книги на первой и второй вместе
3)90-72=18 книг на третьей полке
4)45-18=27 книг
Ответ: на третье полке на 27 книг меньше, чем на первой полке .

Answer 2

45-18=27-на второй полке
45+27=72-на первой и второй полках вместе
90-72=18-на третьей полке.
45-18=27-на 27 книг меньше

Answer 3

Problem Analysis

To solve this problem, we need to determine the number of books on the third shelf and then calculate the difference between the number of books on the first and third shelves.

Solution

1. Let's denote the number of books on the first shelf as x and the number of books on the second shelf as x - 18. 2. We know that the total number of books on the three shelves is 90, so we can set up the equation: x + (x - 18) + (x - ?) = 90.

Calculation

1. The total number of books on the three shelves is 90, so we can solve for x using the equation: x + (x - 18) + (x - ?) = 90. 2. Solving for x: - 3x - 18 - ? = 90 - 3x - ? = 108 - 3x = 108 + ? - x = (108 + ?)/3

Conclusion

The number of books on the third shelf can be calculated using the value of x obtained from the equation. The difference between the number of books on the first and third shelves can then be determined by subtracting the number of books on the third shelf from the number of books on the first shelf.