Question

Arnav is thrice as old as his sister. In 10 years from now , the sum of their ages will be 48 years. How old are they now?​

Answer 1

Arnav's age = 21 years

Sister's age = 7 years

Step-by-step explanation:

Given -

• Arnav is thrice as old as his sister.
• In 10 years from now , the sum of their ages will be 48 years.

To find -

• Arnav and his sister's current age.

Solution -

Let Arnav's sister's age be x years.

Let Arnav's age be 3x years.

Now , according to the second statement ,

(x + 10) + (3x + 10) = 48

→ 4x + 20 = 48

→ 4x = 48 - 20

→ 4x = 28

→ x = 28/4

→ x = 7 years

Hence , Arnav's age => 3x = 3 × 7

= 21 years

Therefore , Arnav's age is 21 years and his sister's age is 7 years.

Answer 2

Answer:

The present age of Arnav's Sister = 7 years

The present age of Arnav = 21 years

Step-by-step explanation:

Let,

• The present age of Arnav's Sister = x
• The present age of Arnav = 3x

After 10 years,

• The age of Arnav's Sister = x + 10
• The age of Arnav = 3x + 10

Also,

★ The sum of their ages will be 48 years.

★ According to the Question :

⇒ (x + 10) + (3x + 10) = 48

⇒ 4x + 20 = 48

⇒ 4x = 48 - 20

⇒ 4x = 28

⇒ x = 28/4

⇒ x = 7

The present age of Arnav's Sister = 7 years

• The present age of Arnav = 3x

⇒ 3x

⇒ 3 (7)

⇒ 21

The present age of Arnav = 21 years

Therefore, the present age of Arnav's Sister and Arnav is 7 years and 21 years respectively.