Question

В библиотеке справочной литературы всего 2%, а детективы занимают много места- они составляют 42% всех книг. Сколько справочников в библиотеке, если детективов 1428 штук?

Answer 1

42%-1428 книг.

2%-х книг.

42:2=1428:х

21=1428:х

21х=1428

х=1428:21

х=68 справочников-в библиотеке.

ОТВЕТ: 68 справочников.

 

Answer 2

если 1428книг ---------------------------- это 42% детективы

        х книг ----------------------------------100% всего книг

х=1428*100:42= 3400 книг-всего в библиотеке.

 

3400книг ------------------------------ это 100%

х книг --------------------------------------это 2% справочники

х=3400*2:100=68 справочников в библиотеке. 

Answer 3

Calculation of the Number of Reference Books in the Library

To calculate the number of reference books in the library, we need to know the total number of books and the percentage of detective books.

Given that detective books make up 42% of all books in the library and there are 1428 detective books, we can set up the following equation:

Number of detective books / Total number of books = Percentage of detective books / 100

Let's solve for the total number of books:

1428 / Total number of books = 42 / 100

To find the total number of books, we can cross-multiply and solve for the unknown:

1428 * 100 = 42 * Total number of books

Total number of books = (1428 * 100) / 42

Now, let's calculate the total number of books:

Total number of books = (1428 * 100) / 42 = 3400

Therefore, there are 3400 books in the library.

Calculation of the Number of Reference Books

We know that reference books make up only 2% of the total books in the library. To find the number of reference books, we can use the following equation:

Number of reference books / Total number of books = Percentage of reference books / 100

Let's solve for the number of reference books:

Number of reference books / 3400 = 2 / 100

To find the number of reference books, we can cross-multiply and solve for the unknown:

Number of reference books = (2 * 3400) / 100

Now, let's calculate the number of reference books:

Number of reference books = (2 * 3400) / 100 = 68

Therefore, there are 68 reference books in the library.

Please note that the calculations provided are based on the given information and assumptions made.