The average of five numbers is $6.9$. If one of the numbers is deleted,the average of the remaining numbers is $4.4$. What is the value of the number deleted?

The average weight of $45$ students in a class is $52 \, kg.$ Five of them whose average weight is $48 \, kg$ leave the class and other $5$ students whose average weight is $54 \, kg$ join the class. What is the new average weight (in $kg$) of the class?

The average age of a cricket team reduces by $2$ when two senior players aged $32$ and $30$ are replaced by $2$ youngsters of equal age. What is the age of these youngsters?

The average of two numbers $A$ and $B$ is $20,$ that of $B$ and $C$ is $19,$ and that of $C$ and $A$ is $21.$ What is the value of $A?$

The average of $13$ results is $50$. If the average of the first $7$ results is $52$ and that of the last $7$ results is $49$,find the $7^{th}$ result.

The average salary of $20$ workers in an office is $Rs. 1900$ per month. If the manager's salary is added,the average becomes $Rs. 2000$ per month. The manager's annual salary (in $Rs.$) is