A cricketer gives $12.4$ runs per wicket. He gives $26$ runs and takes $5$ wicket in a match after which his average becomes $12$ per wicket. How many wickets had been taken till the last match?

A man covers $\frac{1}{3}$ of his journey by train at $80\, km / h ,$ next $\frac{1}{3}$ by $60\, km / h$ and the rest by bicycle at $30 \,km / h$. Find the average speed of the man during the whole journey. (in $km/h$)

The average salary of workers in $AMS$ careers is $Rs.\, 2,000$ , the average salary of faculty being $Rs. \,4,000$ and the management trainees being $Rs. \,$ $1,250 .$ The total number of workers could be

The average salary of $20$ workers in an office is $Rs.\, 1900$ per $month.$ If the manager's salary is added, the average becomes $Rs.\,2000$ per $month.$ The manager's annual salary (in $Rs.$) is

If the average of $m$ numbers is $n^{2}$ and that of $n$ numbers is $m^{2},$ then the average of $( m + n )$ numbers is