What is the average of the first $10$ even numbers?

The arithmetic mean of the following numbers is $1, 2, 2, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7$.

The average of runs of a cricket player in $10$ innings was $32$. How many runs must he make in his next innings so as to increase his average of runs by $4$?

$12 \%$ of Kaushal's monthly salary is equal to $16 \%$ of Nandini's monthly salary. Suresh's monthly salary is half that of Nandini's monthly salary. If Suresh's annual salary is $Rs.\, 1.08$ lakhs,what is Kaushal's monthly salary in $Rs.$?

The average of the test scores of a class of $m$ students is $70$ and that of $n$ students is $91$. When the scores of both the classes are combined,the average is $80$. What is $n / m$?

In a cricket team of $11$ boys,one player weighing $42 \,kg$ is injured and replaced by another player. If the average weight of the team is increased by $100 \,g$ as a result of this,then what is the weight of the new player (in $.1$)? (in $kg$)