Question

В первый день мальчик прочитал 100 страниц, что составило 20 процентов всей книги. во второй день он прочитал 25 процентов всей книги.сколько страниц ему осталось прочитать ? (развернутый ответ пожалуйста)

Answer 1

100*5=500 стр. - всего в книге
500/100*25=125 стр. - прочитал мальчик во второй день
500-(100+125)=275 стр - осталось прочитать

Answer 2

Problem Analysis

We are given that a boy read 100 pages on the first day, which is 20% of the entire book. On the second day, he read 25% of the entire book. We need to determine how many pages he has left to read.

Solution

Let's calculate the total number of pages in the book using the information given. We know that 100 pages represent 20% of the book, so we can set up the following equation:

100 pages = 20% of the book

To find the total number of pages in the book, we can divide both sides of the equation by 20% (or 0.2):

Total number of pages = 100 pages / 0.2

Using this equation, we can calculate the total number of pages in the book.

Next, we need to find out how many pages the boy read on the second day. We are given that he read 25% of the entire book. We can set up the following equation:

Pages read on the second day = 25% of the total number of pages

Using this equation, we can calculate the number of pages the boy read on the second day.

Finally, to find out how many pages the boy has left to read, we subtract the total number of pages he has read from the total number of pages in the book.

Let's calculate the solution step by step.

Calculation

1. Calculate the total number of pages in the book: - 100 pages = 20% of the book - Total number of pages = 100 pages / 0.2 = 500 pages 2. Calculate the number of pages the boy read on the second day: - Pages read on the second day = 25% of the total number of pages - Pages read on the second day = 25% of 500 pages = 125 pages 3. Calculate the number of pages the boy has left to read: - Pages left to read = Total number of pages - Pages read on the first day - Pages read on the second day - Pages left to read = 500 pages - 100 pages - 125 pages = 275 pages

Answer

The boy has 275 pages left to read.

Please let me know if you need any further assistance.