Fifteen movie theatres average $600$ customers per theatre per day. If $six$ of the theaters close down but the total theater attendance stays the same, then the average daily attendance per theatre among the remaining theaters is

The average marks of a student in four subjects is $75 .$ If the student obtained $80$ marks in the $5^{\text {th }}$ subject then the new average is?

The average weight of $24$ students in section $A$ of a class is $58 \,kg,$ whereas the average weight of $26$ students in section $B$ of the same class is $60.5 \,kg$. Find out the average weight of all the $50$ students of the class. (in $kg$)

The average salary of the entire staff in a office is $Rs.\, 120$ per $month.$ The average salary of officers is $Rs.\, 460$ and that of non-officers is $Rs. \,$ $110 .$ If the number of officers is $15,$ then find the number of non-officers in the office ?

The average of $n$ numbers $x_{1}, x_{2}, \ldots, x_{n}$ is $x$. Then, the value of $\sum \limits_{i=1}^{n}\left(x_{i}-\bar{x}\right)$ is equal to

The average of the two-digit numbers, which remain the same when the digits interchange their position is