Question

НУЖНА ПОМОЩЬ ОЧЕНЬ УМНЫХ ЛЮДЕЙ! Реши задачу подбором. Алгебраическим и арифметическим способом!!!!"Сколько лет твоему отцу?"-спросили у Пети. Он ответил так: "Я втрое моложе папы, но зато втрое старше своей сестры, а папе и сестре вместе 50 лет" Сколько лет отцу? ПРОШУ РАССУЖДЕНИЕ С Х-СОМ

Answer 1

П*3+П:3=50
        3П+П/3=50
      (приведём к общему знаменателю )
      (9П+П) : 3 =50
       10П:3=50
        П=15 ( лет Пети )
        Отцу 15*3-45 лет , сестре 15:3=5
       
1)9 + 1 = 10 (ч) - папы и сестры
2) 50 : 10 = 5 (л) - сестре
3)3 * 5 = 15 (л) - Пете
4) 15 * 3 = 45 (л)

Answer 2

Problem Analysis

We are given the following information: - Petia is three times younger than his father. - Petia is three times older than his sister. - The sum of the ages of Petia's father and sister is 50 years.

We need to determine the age of Petia's father.

Algebraic Solution

Let's assume the age of Petia's father is x years.

According to the given information: - Petia's age is x/3 years. - Petia's sister's age is (x/3)/3 = x/9 years.

The sum of the ages of Petia's father and sister is 50 years: x + x/9 = 50

To solve this equation, we can multiply both sides by 9 to eliminate the fraction: 9x + x = 450 10x = 450 x = 45

Therefore, Petia's father is 45 years old.

Arithmetic Solution

Let's use a trial and error approach to find the age of Petia's father.

We know that Petia is three times younger than his father, so we can start by assuming that Petia's age is 1 year. In this case, his father's age would be 3 years.

We also know that Petia is three times older than his sister, so his sister's age would be 1/3 years.

The sum of the ages of Petia's father and sister is 4 years, which is not equal to 50 years. Therefore, we need to increase the ages.

Let's assume Petia's age is 2 years. In this case, his father's age would be 6 years and his sister's age would be 2/3 years. The sum of the ages of Petia's father and sister is 8 2/3 years, which is still not equal to 50 years.

Continuing this process, we find that when Petia's age is 15 years, his father's age is 45 years and his sister's age is 5 years. The sum of the ages of Petia's father and sister is indeed 50 years.

Therefore, Petia's father is 45 years old.

Conclusion

Both the algebraic and arithmetic methods lead to the same conclusion: Petia's father is 45 years old.