$A$ batsman in his $17^{th}$ innings makes a score of $85$ runs,and thereby,increases his average by $3$ runs. What is his average after the $17^{th}$ innings? He had never been 'not out'.

The average age of a board of directors of a company,having $10$ directors,was $48$ years. Coincidentally,when a director aged $53$ resigned from the board,another director died on the same day. $A$ new director aged $34$ joined the board. Next year in the same month,the average age of all the $9$ directors was found to be $46$ years. The age of the late (i.e.,dead) director at the time of his death was (in years):

In an examination,out of $20$ students in a class,in Mathematics $2$ students scored $100$ marks,$3$ students scored $0$,and the average marks for the rest of the students was $40$. What is the average mark of the whole class? (in marks)

The average monthly salary of a staff of $9$ persons is $Rs.\, 2450$. One member of the staff whose monthly salary is $Rs.\, 2650$ is transferred. Find out the average salary of the remaining $8$ persons of the staff (in $Rs.$).

The average monthly salary of all the employees in an industry is $Rs. 12,000$. The average salary of male employees is $Rs. 15,000$ and that of female employees is $Rs. 8,000$. What is the ratio of male employees to female employees?

In a class,there are $20$ boys whose average age is decreased by $2$ months,when one boy aged $18$ years is replaced by a new boy. The age of the new boy is: