Question

Четыре красных шарика и три зелёных стоят 150 рублей.Три красных и четыре зелёных стоят 130 рублей.Сколько стоит один красный и один зелёный шарик

Answer 1

4к+3з=150 → 4к=150-3з→к=(150-3з)/4
подставляем вместо к в это уравнение
3к+4з=130

3(150-3з)/4+4з=130
3(150-3з)+4з/4=130
450-9з+16з=130*4
7з=520-450
7з=70
з=70:7
з=10руб-зеленые

к=(150-3*10):4
к=30руб-красные

Answer 2

1) 150-130=20
2) 150:3=50
3)50-20=30
4)30-20=10

Answer 3

Problem Analysis

We are given two equations: 1. Four red balls and three green balls cost 150 rubles. 2. Three red balls and four green balls cost 130 rubles.

We need to find the cost of one red ball and one green ball.

Solution

Let's assume the cost of one red ball is x rubles and the cost of one green ball is y rubles.

From the first equation, we can write the following equation: 4x + 3y = 150

From the second equation, we can write the following equation: 3x + 4y = 130

We can solve these two equations to find the values of x and y.

Solving the Equations

To solve the equations, we can use the method of substitution or elimination. Let's use the method of elimination.

Multiplying the first equation by 3 and the second equation by 4, we get: 12x + 9y = 450 12x + 16y = 520

Subtracting the first equation from the second equation, we get: 7y = 70 y = 10

Substituting the value of y into the first equation, we get: 4x + 3(10) = 150 4x + 30 = 150 4x = 120 x = 30

Therefore, the cost of one red ball is 30 rubles and the cost of one green ball is 10 rubles.

Answer

The cost of one red ball and one green ball is 30 rubles and 10 rubles, respectively.