$A$ man whose bowling average is $12.4$ takes $5$ wickets for $26$ runs and,thereby,decreases his average by $0.4$. The number of wickets taken by him before his last match is:

The average of three consecutive odd numbers is $12$ more than one-third of the first of these numbers. What is the last of the three numbers?

The average age of a family of $6$ members is $22 \text{ years}$. If the age of the youngest member is $7 \text{ years}$,then what was the average age of the family at the birth of the youngest member?

The average marks of $40$ students in an examination was $25$. It was later found that the marks of one student had been wrongly entered as $73$ instead of $37$. What is the value of the correct average?

The average of $50$ numbers is $38$. If two numbers,namely $45$ and $55$,are discarded,the average of the remaining numbers is

The average speed of a train running at a speed of $30 \, km/h$ during the first $100 \, km$,at $40 \, km/h$ during the second $100 \, km$,and at $50 \, km/h$ during the last $100 \, km$ is nearly (in $km/h$):