Question

игорь на 4 года старше своего брата алексея и на 5 лет младше сестры маши.если сложить весь возраст,то получится 34 года.сколько лет игорю?

Answer 1

х лет - Алексею

х+4 года - Игорю

х+4+5=х+9 лет - Маше

х+х+4+х+9=34

3х=21

х=7 (лет) - Алексею

7+4=11 (лет) - Игорю

11+5=16 (лет) - Маше                                                                                                 

Answer 2

x лет - Алексею

х+4 года - Игорю

х+4+5=х+9 лет - Маше

х+х+4+х+9=34

3х=21

х=7

7+4=11

11+5=16  

Значит, 7 лет Алексею, 11 лет Игорю и 16 лет Маше.

Answer 3

Problem Analysis

We are given that Igor is 4 years older than his brother Alexey and 5 years younger than his sister Masha. The sum of their ages is 34 years. We need to determine Igor's age.

Solution

Let's assume Igor's age is x. Based on the given information, we can set up the following equations:

1. Igor's age + Alexey's age = 34 - Masha's age 2. Igor's age = Alexey's age + 4 3. Igor's age = Masha's age - 5

We can solve this system of equations to find Igor's age.

Substituting equation 2 into equation 1, we get:

(Alexey's age + 4) + Alexey's age = 34 - Masha's age

Simplifying, we have:

2 * Alexey's age + 4 = 34 - Masha's age

Rearranging, we get:

2 * Alexey's age + Masha's age = 30

Substituting equation 3 into equation 1, we get:

(Masha's age - 5) + Alexey's age = 34 - Masha's age

Simplifying, we have:

2 * Masha's age + Alexey's age = 39

Now we have a system of two equations:

2 * Alexey's age + Masha's age = 30 2 * Masha's age + Alexey's age = 39

We can solve this system of equations to find the values of Alexey's age and Masha's age.

Let's solve it using the substitution method:

From equation 1, we can express Alexey's age in terms of Masha's age:

Alexey's age = 15 - Masha's age / 2

Substituting this into equation 2, we get:

2 * Masha's age + (15 - Masha's age / 2) = 39

Simplifying, we have:

4 * Masha's age + 15 - Masha's age = 78

Combining like terms, we get:

3 * Masha's age = 63

Dividing both sides by 3, we find:

Masha's age = 21

Substituting this back into equation 2, we can find Alexey's age:

Alexey's age = 15 - 21 / 2 = 15 - 10.5 = 4.5

Finally, we can find Igor's age by substituting Masha's age into equation 3:

Igor's age = 21 - 5 = 16

Therefore, Igor is 16 years old.

Answer

Igor is 16 years old.