The mean weight of $34$ students of a school is $42 \,kg$. If the weight of the teacher be included, the mean rises by $400 \,g$. Find the weight of the teacher (in $kg$).

Last year, $5$ companies had an average of $16$ non working days each, and $2$ companies had $5$ fewer non working days each. What was the average number of non working days given by the same companies this $year$ ?

Average temperature of first $4 \,days$ of a week is $38.6^{\circ} C$ and that of the last $4\, days$ is $40.3^{\circ} C$. If the average temperature of the week be $39.1^{\circ} C$, the temperature on $4^{th}$ day is. (in $^{\circ} C$)

The average of $5$ consecutive $integers$ starting with $'m'$ is $n.$ What is the average of $6$ consecutive $integers$ starting with $(m+2) \,?$

There were $35$ students in a hostel. If the number of students increases by $7,$ the expenses of the mess increase by $Rs. \,42$ per $day$ while the average expenditure per head decreases by $Rs.\, 1 .$ Find the original expenditure of the mess in $Rs.$

The average of five numbers is $27 .$ If one number is excluded, the average becomes $25 .$ The excluded number is