The average of odd numbers upto $100$ is ?

The average age of a class of $30$ students and a teacher reduce by $0.5 \,years$ if we exclude the teacher. If the initial average is $14 \,years,$ find the age of the class teacher in $year$ ?

A batsman has a certain average of runs for $12$ innings. In the $13^{th}$ innings, he scores $96$ runs and thereby increasing his average by $5$ runs. What is his average after the $13^{th}$ innings ?

The average salary of all workers in a workshop is $Rs.\, 12000 .$ The average salary of $7$ technicians is $Rs.\, 15000$ and the aterage salary of the rest in $Rs.\, 9000$. The total number of workers in the workshop is:

A librarian purchased $50$ $story-books$ for his library. But he saw that he could get $14$ more books by spending $Rs.\, 76$ more and average price per book would be reduced by $Rs.\,1.$ The average price (in $Rs.$) of each book he bought, was

The average expenditure of a man for the first five months is $Rs.\, 120$ and for the next seven months is $Rs. \,130$ . His monthly average income in $Rs.$ if he saves $Rs. \,290$ in that year, is