What is the average of all numbers between $8$ and $74$ which are divisible by $7\, ?$

The average of $13$ results is $50$. If the average of the first $7$ results is $52$ and that of the last $7$ results is $49$,find the $7^{th}$ result.

The average of marks obtained by $120$ candidates was $35.$ If the average of marks of passed candidates was $39$ and that of failed candidates was $15,$ the number of candidates who passed the examination is

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

The average of five consecutive positive integers is $n$. If the next two integers are also included,the average of all these integers will

The average of $8$ numbers is $20$. The average of the first two numbers is $15 \frac{1}{2}$ and that of the next three is $21 \frac{1}{3}$. If the sixth number is less than the seventh and eighth numbers by $4$ and $7$ respectively,then the eighth number is: