David obtained $76, 65, 82, 67$ and $85$ marks (out of $100$) in English,Mathematics,Physics,Chemistry,and Biology. What is his average marks?

The average weight of $8$ sailors in a boat is increased by $1 \, kg$ if one of them weighing $56 \, kg$ is replaced by a new sailor. The weight of the new sailor is (in $kg$):

The average weight of $36$ students is $50 \,kg$. It was found later that the figure of $37 \,kg$ was misread as $73 \,kg$. What is the correct average? (in $kg$)

The average salary of all the workers in a workshop is $Rs. 8000$. The average salary of $7$ technicians is $Rs. 12000$ and the average salary of the rest is $Rs. 6000$. The total number of workers in the workshop is

In an entrance examination,Ritu scored $56$ percent marks,Smita scored $92$ percent marks,and Rina scored $634$ marks. The maximum marks of the examination is $875$. What is the average marks scored by all the three girls together?

The average age of a group of $18$ persons is $32$ $years$ and $6$ $months$. If two persons of age $65$ $years$ each and one person of age $50$ $years$ leave the group,the average age of the remaining persons in the group will be (in $years$)