The average monthly salary of a staff of $9$ persons is $Rs.\, 2450$. One member of the staff whose monthly salary is $Rs.\, 2650$ is transferred. Find out the average salary of the remaining $8$ persons of the staff (in $Rs.$).

The average weight of $3$ men $A, B$ and $C$ is $84 \, kg$. Another man,$D$,joins the group,and the average weight becomes $80 \, kg$. If another man,$E$,whose weight is $3 \, kg$ more than that of $D$,replaces $A$,then the average weight of $B, C, D$ and $E$ becomes $79 \, kg$. The weight of $A$ is (in $kg$):

The average age of $11$ players of a cricket team is increased by $2 \, \text{months}$ when two of them aged $18 \, \text{years}$ and $20 \, \text{years}$ are replaced by two new players. The average age of the new players is?

The mean of marks secured by $50$ students in division $A$ of class $X$ is $61$,$25$ students of division $B$ is $57$,and that of $50$ students of division $C$ is $55$. What will be the mean of marks of the students of three divisions of Class $X$?

The average salary of all the workers in a workshop is $Rs. 8000$. The average salary of $7$ technicians is $Rs. 12000$ and the average salary of the rest is $Rs. 6000$. The total number of workers in the workshop is

The average of $41$ consecutive odd numbers is $49$. What is the largest number?