The average weight of a class of $24$ students is $35 \,kg$. If the weight of the teacher is included the average rises by $400\, g.$ The weight of the teacher is (in $kg$)

There are $35$ students in a hostel. If the number of students increased by $7,$ the expenses of the mess were increased by $Rs.\,42$ per $day$ while the average expenditure per head decreased by $Rs.\,1$, Find out the actual expenditure of the mess. (in $Rs.$ )

The average revenue of $13$ consecutive years of a company $Rs.\, 70$ $\,lakhs.$ If the average of first $7 \,years$ is $Rs.\, 65$ $\,lakhs$ and that of last $7\, years$ is $Rs.\, 77$ $\,akhs,$ find the revenue for the $7^{th}$ $year.$ (Rs. in $lakh$)

The average of nine numbers is $50.$ The average of the first five numbers is $54$ and that of the last three numbers is $52 .$ Then the sixth number is?

The average monthly income of $P$ and $Q$ is $Rs.\,5050.$ The average monthly income of $Q$ and $R$ is $Rs.\,6250$ and the average monthly income of $P$ and $R$ is $Rs.\,5200.$ The monthly income of $P$ is