Correct Answer - Option 2 : 24

Sum of ages of all the members in the group = 22 × 4 = 88 years

The ratio of ages of their ages is 7 ∶ 9 ∶ 13 ∶ 15

⇒ Let their ages be 7x, 9x, 13x and 15x

∴ 7x + 9x + 13x + 15x = 88

⇒ 44x = 88

⇒ x = 2

∴ Sum of the age of the oldest person and second youngest person of the group = 15x + 9x = 24x

⇒ Sum of the ages = 24 × 2 = 48 years

∴ Average age = 48/2 = 24

**∴ The average age of the oldest person and second youngest person of the group is 24 years.**