Question

три звена класса собрали для школьной библиотеке 65книг.1звено собрано на 10 книг меньше, чем 2звено,а 3 -30% того числа книг которое собрали 1 и 2 звено вместе. Сколько. книг собрал каждое звено

Answer 1

Problem Analysis

We are given that three classes collected a total of 65 books for the school library. The first class collected 10 books fewer than the second class, and the third class collected 30% of the total number of books collected by the first and second classes combined. We need to determine how many books each class collected.

Solution

Let's assign variables to represent the number of books collected by each class: - Let's call the number of books collected by the first class 'x'. - The second class collected 10 books more than the first class, so the number of books collected by the second class is 'x + 10'. - The third class collected 30% of the total number of books collected by the first and second classes combined. The total number of books collected by the first and second classes is 'x + (x + 10) = 2x + 10'. Therefore, the number of books collected by the third class is '0.3 * (2x + 10)'.

We know that the total number of books collected by all three classes is 65. We can set up the following equation to solve for 'x':

x + (x + 10) + 0.3 * (2x + 10) = 65

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

Calculation

x + (x + 10) + 0.3 * (2x + 10) = 65

Simplifying the equation: 2x + 10 + 0.6x + 3 = 65 2.6x + 13 = 65 2.6x = 52 x = 52 / 2.6 x = 20

Answer

The first class collected 20 books. The second class collected 30 books (20 + 10). The third class collected 15 books (0.3 * (2 * 20 + 10)).

Therefore, the first class collected 20 books, the second class collected 30 books, and the third class collected 15 books.