From a group of 15 casting directors of a Bollywood film, four directors aged 18 years, 19 years, 17 years, and 15 years were removed and replaced by four new directors, the average age of the group increased by 4 months. Find the average age of the newly joined directors.

Correct option is A

Ans. (a) 18 years 6 months
Sol.
Step 1: Calculate the total age of the removed directors
The removed directors had ages: 18, 19, 17, and 15 years.
Total age of removed directors=18+19+17+15=69 years\text{Total age of removed directors} = 18 + 19 + 17 + 15 = 69 \text{ years}Total age of removed directors=18+19+17+15=69 years
Step 2: Calculate the total increase in age
The average age of the group increased by 4 months (4/12 years) for 15 directors:
Total increase in age=15× 4/12 =5 years
Step 3: Calculate the total age of the new directors
Total age of new directors=69+5=74 years
Step 4: Find the average age of the newly joined directors
Average age= 74 /4 =18.5 years=18 years 6 months