Question

В классе мальчиков в два раза больше, чем девочек. Если из этого класса уйдут два мальчика и придут две девочки, то девочек будет на 6 меньше, чем мальчиков. Сколько учеников в данном классе?

Answer 1

девочек х

мальчиков 2х

затем стало:

девочек х+2

мальчиков 2х-2

составим уравнение

(2х-2)-(х+2)=6

2х-2-х-2=6

х=6+2+2

х=10 девочек

10*2=20 мальчиков

10+20=30 всего

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Answer 2

Problem Analysis

We are given the information that there are twice as many boys as girls in a class. If two boys leave and two girls join, there will be 6 fewer girls than boys. We need to determine the total number of students in the class.

Solution

Let's assume the number of girls in the class is G and the number of boys is B.

According to the given information, we have the following equations:

1. B = 2G (There are twice as many boys as girls in the class) 2. B - 2 = G + 2 (If two boys leave and two girls join, there will be 6 fewer girls than boys)

We can solve this system of equations to find the values of B and G.

Solving the System of Equations

Let's substitute the value of B from equation 1 into equation 2:

2G - 2 = G + 2

Simplifying the equation:

G = 4

Now, substitute the value of G into equation 1 to find B:

B = 2 * 4 = 8

Therefore, there are 8 boys and 4 girls in the class. The total number of students in the class is:

Total students = Boys + Girls = 8 + 4 = 12

So, there are 12 students in the class.

Answer

There are 12 students in the given class.