Correct Answer - Option 3 : 15 years
Given:
The age of two male students is 20 years and 24 years, respectively.
Formula Used:
Average Age = (Sum of all the ages)/(Total number of students)
Calculation:
Age of the female student = half of the younger student
⇒ Age of the newly joined female student = (1/2) × 20 = 10 years
The new total age = 10 + 20 = 30 years
∴ New average age = 30/2 = 15 years