Question

Ученик прочитал сначала 8/15 всей книги, потом 1/4 остатка.После этого оказалось , что он прочитал на 18 страниц больше, чем ему осталось читать . сколько страниц в книге?

Answer 1

Прочитал 8/15 - значит осталось
1)  1 - 8/15 = 7/15 - осталось после первого дня.
2)  7/15 * 1/4 = 7/60 - прочитал за второй день.
3) 8/15+ 7/60 = 13/20 - прочитал за два дня.
4) 1 - 13/20 = 7/20 - осталось прочитать
5) 13/20 - 7/20 = 6/20  книги = 18 страниц.
6)  18 : 6/20 = (18/6)*20 = 60 стр - вся книга - ОТВЕТ.

Answer 2

Problem Analysis

The problem states that a student read 8/15 of the entire book first, and then read 1/4 of the remaining pages. After this, it was found that the student had read 18 pages more than the number of pages left to read. 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 x.

The student first read 8/15 of the book, which is equal to (8/15) * x pages.

After that, the student read 1/4 of the remaining pages. The remaining pages can be calculated as (1 - 8/15) * x = (7/15) * x pages. Therefore, the number of pages read in the second part is (1/4) * (7/15) * x = (7/60) * x pages.

According to the problem, the student read 18 pages more than the number of pages left to read. So, we can set up the equation:

(8/15) * x + (7/60) * x = (7/15) * x + 18

To solve this equation, we can multiply both sides by 60 to eliminate the denominators:

(8 * 60/15) * x + (7 * 60/60) * x = (7 * 60/15) * x + 18 * 60

Simplifying the equation:

32x + 7x = 28x + 1080

39x = 28x + 1080

11x = 1080

x = 1080 / 11

x ≈ 98.18

Therefore, the total number of pages in the book is approximately 98.

Answer

The total number of pages in the book is approximately 98.