The average of $6$ numbers is $8$. What is the $7^{th}$ number so that the average becomes $10$?

What is the average of first $7$ multiples of $7$?

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 class of $100$ students,the mean marks obtained in a subject is $30$ and in another class of $50$ students the mean marks obtained in the same subject is $60$. The mean marks obtained by the students of two classes taken together is

In a set of prime and composite numbers,the number of composite numbers is twice the number of prime numbers,and the average of all the numbers in the set is $9$. If the number of prime numbers and composite numbers are exchanged,then the average of the set of numbers increases by $2$. If,during the exchange of the numbers,the average of the prime numbers and composite numbers individually remained constant,then what was the ratio of the average of composite numbers to the average of prime numbers (initially)?

The average value of the numbers $15, 21, 32, 35, 46, x, 59, 65, 72$ should be greater than or equal to $43$ but less than or equal to $44$. Then the value of $x$ should be