Correct Answer - Option 2 : 24.3 yrs
Given:
Total student = 12
Average age = 24 years
The age of the student who left the class = 22 and 23 years
Formula used:
Average = The sum of all student age/Total number of student
Calculation:
Average = The sum of all student age/Total number of student
⇒ 24 = The sum of all student age/12
⇒ The sum of all student age = 288
According to the question,
The sum of the ages of student who left the class = 22 + 23
⇒ The sum of the ages of student who left the class = 45
Now,
The age of remaining students = 288 - 45
⇒ The age of remaining students = 243
The number of remaining student = 10
New average,
Average = 243/10
⇒ Average = 24.3
∴ The new average of the class is 24.3 years.
