The average expenditure of a man for the first five months is $Rs.\, 3600$ and for the next seven months it is $Rs.\, 3900$. If he saves $Rs.\, 8700$ during the year,his average income per month is (in $Rs.$)

The average of runs of a cricket player in $10$ innings was $32$. How many runs must he make in his next innings so as to increase his average of runs by $4$?

The average age of mother,father,and son was $42$ years at the time of the son's marriage. After one year,an infant was born in the family,and after $6$ years of marriage,the average age of the family is $36$ years. What was the age of the bride at the time of marriage in years?

Out of seven given numbers,the average of the first four numbers is $4$ and that of the last four numbers is also $4$. If the average of all the seven numbers is $3,$ then the fourth number is?

$A$ batsman has an average of $30$ runs in his $42$ innings. The difference between his maximum and minimum score is $100$. If these two innings are removed,his average for $40$ innings comes down to $28$. What is his minimum score?

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