The average monthly expenditure of a family for the first four months is $Rs.\, 2570$, for the next three months $Rs.\, 2490$ and for the last five months $Rs.\,3030.$ If the family saves $Rs.\, 5320$ during the whole $year,$ the average monthly income of the family during the year is (in $Rs.\,$) 

The bowling average of a cricketer was $12.4 .$ He improves his bowling average by $0.2$ points, when he takes $5$ wickets for $26$ runs in his last match. The number of wickets taken by him before the last match Was?

The average of first $46$ natural number is

Eleven years earlier the average age of a family of $4$ members was $28 \,years.$ Now the age of the same family with six members js yet the same, even when $2$ children were born in this period. If they belong to the same parents and the age of the first child at the time of the birth of the younger child was same as there were total family members just after the birth of the youngest member of this family, then the present age of the youngest member of the family is in $year$?

A person travelled from one place to another at an average speed of $40 \,km / h$ and back to the original place at an average speed of $50\, km / h$. What is his average speed in $km / h$ during the entire trip?

The average salary, per head, of all the workers of an institution is $Rs.\, 60 .$ The average salary of $12$ officers is $Rs.\, 400$; the average salary, per head, of the rest is $Rs.\,56.$ The total number of workers in the institution is