The average of $10$ numbers is $7$. What will be the new average if each of the numbers is multiplied by $8$?

The average score of Sachin after $25$ innings is $46$ runs per innings. If after the $26^{th}$ innings,his average runs increased by $2$ runs,then what is his score in the $26^{th}$ innings?

The average salary of all workers in a workshop is $Rs. 12000$. The average salary of $7$ technicians is $Rs. 15000$ and the average salary of the rest is $Rs. 9000$. The total number of workers in the workshop is:

The average age of $36$ students in a group is $14$ years. When the teacher's age is included, the average increases by $1$. What is the teacher's age in years?

Three years ago,the average age of a family of $5$ members was $27 \text{ years}$. After the addition of a child to the family,the present average age of the family is still $27 \text{ years}$. Find the present age of the child (in years).

There was one mess for $30$ boarders in a certain hostel. On the number of boarders being increased by $10,$ the expenses of the mess were increased by $Rs.\, 40$ per month while the average expenditure per head diminished by $Rs.\, 2.$ Find out the actual monthly expenses (in $Rs.$).