The average of the first nine prime numbers is:

What is the average of all numbers between $100$ and $200$ which are divisible by $13$ (in $.5$)?

The average age of $5$ boys is $16$ years, of which the average age of $4$ boys is $16$ years $3$ months. The age of the $5^{th}$ boy is:

The average marks of a class of $35$ children is $35$. The marks of one of the students,who got $35$,was incorrectly entered as $65$. What is the correct average of the class?

The average marks obtained by $40$ students of a class is $86$. If the $5$ highest marks are removed,the average reduces by $1$ mark. The average marks of the top $5$ students is

The total marks obtained by a student in Physics,Chemistry and Mathematics together is $120$ more than the marks obtained by him in Chemistry. What is the average marks obtained by him in Physics and Mathematics together?