Question

В трёх классах учится 77 детей.Кол-во 1в класса составляет 2/3 (две третьих) количества 1а класса, а количество 1б класса 90% от 1а.Сколько детей учится в каждом классе? Составьте уравнение СРОЧНО заранее спасибо

Answer 1

1 в 20 1 б 27 1 а 30

Answer 2

Problem Analysis

We are given that there are three classes with a total of 77 students. The number of students in the 1a class is 2/3 of the total number of students in the 1st class, and the number of students in the 1b class is 90% of the number of students in the 1a class. We need to find the number of students in each class.

Solution

Let's assume the number of students in the 1st class is x. According to the given information, the number of students in the 1a class is 2/3 of x, and the number of students in the 1b class is 90% of the number of students in the 1a class.

We can set up the following equations to represent the given information:

Equation 1: x + (2/3)x + (90/100)(2/3)x = 77

Simplifying Equation 1, we get:

(1 + 2/3 + (90/100)(2/3))x = 77

(1 + 2/3 + 6/15)x = 77

(15/15 + 10/15 + 6/15)x = 77

(31/15)x = 77

x = (15/31) * 77

x ≈ 37.516

Since we cannot have a fraction of a student, we can round x to the nearest whole number, which is 38.

Now, we can calculate the number of students in each class:

Number of students in the 1st class (x) ≈ 38

Number of students in the 1a class = (2/3)x ≈ (2/3) * 38 ≈ 25.333

Rounding the number of students in the 1a class to the nearest whole number, we get:

Number of students in the 1a class ≈ 25

Number of students in the 1b class = (90/100)(2/3)x ≈ (90/100)(2/3) * 38 ≈ 22.8

Rounding the number of students in the 1b class to the nearest whole number, we get:

Number of students in the 1b class ≈ 23

Therefore, the number of students in each class is approximately:

1st class: 38 students 1a class: 25 students 1b class: 23 students

Answer

Approximately, there are 38 students in the 1st class, 25 students in the 1a class, and 23 students in the 1b class.