$A$ batch of $60$ students made an average score of $50$ marks and another batch of $40$ students made an average score of $45$ marks. What is the overall average score?

The sum of three consecutive even numbers is $28$ more than the average of these three numbers. Then the smallest of these three numbers is

The average age of $A, B, C, D$ five years ago was $45$ years. By including $x$,the present average age of all the five is $49$ years. The present age of $x$ is (in years):

After replacing an old member with a new member,it was found that the average age of five members of a club is the same as it was $3 \, \text{years}$ ago. What is the difference between the ages of the replaced member and the new member (in $\text{years}$)?

The average of the first nine prime numbers is

What is the age of a class teacher?
$I.$ There are $11$ students in the class.
$II.$ The average age of the students and the teacher is $14$ years.
$III.$ The average age of the teacher and the students is $3$ years more than that of the students.