Question

На полке лежали книги. Взяли 30%. Потом из оставшихся книг взяли 75% . Осталось 14 книг. Сколько книг было в начале? Решите пожалуйста срочно!!!!!

Answer 1

1)100-30=70% осталось на полке после того как взяли первый раз
75%=0,75
2)70*0,75=52,5 % взяли во второй раз
3)70-52,5=17,5% осталось на полке после того как взяли два раза
17,5%=0,175
4)14:0,175=80 книг было
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Answer 2

Problem Analysis

We are given that there were some books on a shelf. First, 30% of the books were taken, and then 75% of the remaining books were taken. We are also told that there were 14 books left. We need to determine the total number of books that were initially on the shelf.

Solution

Let's assume that the total number of books initially on the shelf is represented by the variable x.

After taking 30% of the books, we are left with 70% of the books. This can be represented as 0.7x.

Then, after taking 75% of the remaining books, we are left with 25% of the books. This can be represented as 0.25 * 0.7x.

According to the problem, we are told that there are 14 books left. So we can set up the equation:

0.25 * 0.7x = 14

To find the value of x, we can solve this equation.

Calculation

Let's solve the equation:

0.25 * 0.7x = 14

0.175x = 14

x = 14 / 0.175

x = 80

Answer

There were 80 books initially on the shelf.

Explanation

Initially, there were 80 books on the shelf. 30% of 80 is 24, so 24 books were taken. This leaves 56 books on the shelf. Then, 75% of 56 is 42, so 42 books were taken. This leaves 14 books on the shelf, which matches the information given in the problem.

Therefore, the answer is 80 books.