Question

Мальчик в первый день прочитал треть книги и еще 12 страниц, а во второй день 25% оставшегося числа страниц и последние 9 страниц. Сколько страниц в книге? Решите не алгебраическим способом!​

Answer 1

Пошаговое объяснение:

нужно сзади смотреть. 25% от оставшегося + 9 стр то есть 9стр то есть 9 стр =75% то есть 100%=12 стр 100%-12 стр -12 стр =1\3 от 100% то есть 1\3=12 стр то есть 100%= 36 стр

Answer 2

Problem Analysis

We are given the information that a boy read one-third of a book on the first day, plus an additional 12 pages. On the second day, he read 25% of the remaining pages, plus the last 9 pages. We need to determine the total number of pages in the book.

Solution

Let's assume the total number of pages in the book is represented by the variable x.

On the first day, the boy read one-third of the book, which is x/3 pages. He also read an additional 12 pages. So, the total number of pages read on the first day is x/3 + 12.

On the second day, the boy read 25% of the remaining pages. The remaining pages can be calculated by subtracting the pages read on the first day from the total number of pages: x - (x/3 + 12). The boy also read the last 9 pages. So, the total number of pages read on the second day is 0.25 * (x - (x/3 + 12)) + 9.

The total number of pages read by the boy is the sum of the pages read on the first and second days. This should be equal to the total number of pages in the book, x.

We can set up the equation as follows:

x/3 + 12 + 0.25 * (x - (x/3 + 12)) + 9 = x

Now, let's solve this equation to find the value of x.

Solution Steps

1. Simplify the equation by combining like terms. 2. Solve the equation for x.

Solution

1. Simplifying the equation: - Distribute 0.25 to the terms inside the parentheses: x/3 + 12 + 0.25x - 0.25(x/3) - 0.25(12) + 9 = x - Simplify the expression inside the parentheses: x/3 + 12 + 0.25x - (0.25/3)x - 3 + 9 = x - Combine like terms: x/3 - (0.25/3)x + 0.25x + 12 + 9 - 3 = x - Combine like terms: (x/3 - (0.25/3)x + 0.25x) + 18 - 3 = x - Combine like terms: (x/3 + (0.25 - 0.25/3)x) + 15 = x - Combine like terms: (x/3 + (0.75/3)x) + 15 = x - Combine like terms: (x/3 + (3/4)x) + 15 = x - Combine like terms: (4x/12 + 9x/12) + 15 = x - Combine like terms: (13x/12) + 15 = x - Move x to the left side of the equation: (13x/12) - x + 15 = 0 - Multiply the entire equation by 12 to eliminate the fraction: 13x - 12x + 180 = 0 - Combine like terms: x + 180 = 0 - Subtract 180 from both sides of the equation: x = -180

2. The solution to the equation is x = -180. However, since the number of pages in a book cannot be negative, this solution is not valid.

Conclusion

Based on the given information, it is not possible to determine the total number of pages in the book. The equation does not have a valid solution.