Correct Answer - Option 2 : 21 years

**Given:**

The average age of Shikha and Yashika = 24 years

After 10 years the ratio of Yashika and Shikha's age = 8 ∶ 9

**Concept used:**

Average = (Total sum)/(Total number)

**Calculations:**

The total sum of Shikha and Yashika's present age = 24 × 2 = 48

Let Yashika and Shikha's age after 10 years be 8x and 9x respectively

So, the present age of Yashika = 8x – 10

The present age of Shikha = 9x – 10

The total sum of present age = 8x – 10 + 9x – 10

⇒ 17x – 20 = 48

⇒ 17x = 68

⇒ x = 4

The present age of Shikha = 9x – 10

⇒ 9(4) – 10 = 26 years

Before 5 years the age of Shikha = 26 – 5 = 21 years

**∴ Before 5 years the age of Shikha is 21 years**