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

Average weight of $25$ persons is increased by $1 \,kg ,$ when one man weighing $60\, kg$ is replaced by a new person. Weight of new person is? (in $kg$)

The average weight of five persons sitting in a boat is $38\, kg.$ The average weight of the boat and the persons sitting in the boat is $52\, kg.$ What is the weight of the boat (in $kg$)?

The average age of $8$ men is increased by $2\, years.$ When $2$ of them, whose ages are $20\, years$ and $24 \,years$ respectively, are replaced by $2$ women. What is the average age of these two women ? (in $years$)

The average salary of the entire staff in a office is $Rs.\, 120$ per $month.$ The average salary of officers is $Rs.\, 460$ and that of non-officers is $Rs. \,$ $110 .$ If the number of officers is $15,$ then find the number of non-officers in the office ?

A number, $x,$ equals $80 \%$ of the average of $5,7,$ $14$ and a number $y$. If the average of $x$ and $y$ is $26$ then value of $y$ is