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 age of a group of $15$ students is $10 \, \text{years}$. When $5$ more students joined the group,the average age increased by $1 \, \text{year}$. If the average age of the $5$ new students is $x$,find the value of $x$ (in $\text{years}$).

In an examination,the average marks obtained by the girls of a class is $85$ and the average marks obtained by the boys of the same class is $87$. If the girls and boys are in the ratio $4:5$,the average marks of the whole class (approx.) is closest to:

If the average of $m$ numbers is $n^{2}$ and that of $n$ numbers is $m^{2}$,then the average of $(m + n)$ numbers is

$A, B, C$ and $D$ are four consecutive even numbers,respectively,and their average is $65$. What is the product of $A$ and $D$?

The average of five consecutive even numbers starting with $4$ is: