Question

Ірині та її мамі 36 років, а сума років її мами та її бабусі 81рік. Скільки років було бабусі, коли народилася Ірина?

Answer 1

Запишем:
И+М=36
Б+М=81
Видим, что бабушка старше Ирины на 81-36=45 лет
Значит, бабушке было 45 лет 

Answer 2

Calculation of the Grandmother's Age

To determine the age of the grandmother when Irina was born, we can use the information provided.

We know that Irina and her mother have a combined age of 36 years, and the sum of her mother's age and her grandmother's age is 81 years.

Let's denote Irina's age as "I," her mother's age as "M," and her grandmother's age as "G."

From the given information, we can write two equations:

1. Irina's age plus her mother's age equals 36: I + M = 36 2. The sum of her mother's age and her grandmother's age equals 81: M + G = 81

To find the grandmother's age, we need to solve these equations simultaneously.

Let's solve the equations:

From equation 1, we can express Irina's age (I) in terms of her mother's age (M): I = 36 - M

Substituting this expression for I in equation 2, we get: (36 - M) + G = 81

Simplifying the equation, we have: G = 81 - 36 + M

Now, we can substitute this expression for G in equation 2: M + (81 - 36 + M) = 81

Simplifying further, we get: 2M + 45 = 81

Subtracting 45 from both sides of the equation, we have: 2M = 36

Dividing both sides of the equation by 2, we find: M = 18

Now that we know Irina's mother's age is 18, we can substitute this value back into equation 1 to find Irina's age: I + 18 = 36

Subtracting 18 from both sides of the equation, we get: I = 18

Therefore, Irina is 18 years old.

To find the grandmother's age when Irina was born, we can substitute Irina's age (18) into equation 2: 18 + G = 81

Subtracting 18 from both sides of the equation, we find: G = 63

Therefore, the grandmother was 63 years old when Irina was born.

So, to answer the question, the grandmother was 63 years old when Irina was born.