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 $Rs.$
$420$
$520$
$450$
$550$
The average age of students of a class is $15.8 \,years.$ The average age of boys in the class is $16.4$ $years$ and that of the girls is $15.4\, years.$ The ratio of number of boys to the number of girls in the class is:
The average salary per head of all the workers in a workshop is $Rs.\,850.$ If the average salary per head of $7$ technicians is $Rs.\, 1000$ and the average salary per head of the rest is $Rs.\, 780,$ find out the total number of workers in the workshop.
The batting aterage for $40$ innings of a cricketer is $50$ nuns. His highest score exceeds his lowest score by $172$ runs. If these two innings are excluded, the average of the remaining $38$ innings is $48$ runs. The highest score of the player is
The average of $10$ mumbers is $7 .$ What will be the new average if each of the numbers is multiplied by $8 \,?$
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 $kg$).