The average salary of the entire staff in an office is $Rs.\, 500$ per day. The average salary of officers is $Rs.\, 750$ and that of non-officers is $Rs. \,$ $250 .$ If the number of officers is $15,$ then find the number of nonofficers in the office?
$25$
$10$
$15$
$20$
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 $kg$)
Average of ten numbers is calculated. If each number was increased by $12 \%$, then the average
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?
$16$ children are to be divided into two groups $A$ and $B$ of $10$ and $6$ children, respectively. The average marks obtained by the children of group $A$ is $75$ and that of all the children is $76 .$ Then, the average marks of the children of group $B$ is ?
There were $35$ students in a hostel. If the number of students increases by $7 ,$ the expenses of the mess increase by $Rs.\,42$ per $day$ while the average expenditure per head diminishes by $Rs.\,1$ Find the actual expenditure of the mess. (in $Rs.$)