In a school, the average age of students is $6 \,years$ , and the average age of $12$ teachers is $40\, years.$ If the average age of the combined group of all the teachers and students is $7 \,years$ , then the number of students is?

The average of $5$ consecutive $integers$ starting with $'m'$ is $n.$ What is the average of $6$ consecutive $integers$ starting with $(m+2) \,?$

In a $20$ over match, the required run rate to win is $7.2 .$ If the run rate is $6$ at the end of the $15^{th}$ over, the required run rate to win the match is

The average age of $5$ sisters is $20 \,year.$ If the age of the youngest sister be $4 \,year,$ what was the average age of the group of sisters at the birth of the youngest sister in $year$ ?

In a coconut grove, $(x+2)$ trees yield $60$ $nuts$ per $year,$ $x$ trees yield $120\, nuts$ per $ year,$ and $(x-2)$ trees yield $180 \,nuts$ per $year$. If the average yield per $year$ per tree be $100,$ find the value of $x .$

The average age of $6$ members of a family is $20\, years.$ If the age of a servant is included, the average age increased by $25 \%$. What is the age (in $years$) of the servant ?