The average marks in English subject of a class of $24$ students is $56$. If the marks of three students were misread as $44, 45$ and $61$ instead of the actual marks $48, 59$ and $67$ respectively,then what would be the correct average?

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

The average age of Sachin $(S)$ and Ganguli $(G)$ is $35 \text{ years}$. If Kaif $(K)$ replaces Sachin,the average age becomes $32 \text{ years}$,and if Kaif $(K)$ replaces Ganguli $(G)$,the average age becomes $38 \text{ years}$. If the average age of Dhoni $(D)$ and Irfan $(I)$ is half of the average age of Sachin,Ganguli,and Kaif,then the average age of all the five people is:

$3 \, \text{years}$ ago,the average age of a family of $5 \, \text{members}$ was $17 \, \text{years}$. With the birth of a new baby,the average age of the $6 \, \text{members}$ remains the same even today. Find the age of the new baby in years.

The average weight of a group of $20$ boys was calculated to be $89.4 \text{ kg}$ and it was later discovered that one weight was misread as $78 \text{ kg}$ instead of the correct one of $87 \text{ kg}$. The correct average weight is in $\text{kg}$.

In a school with $600$ students,the average age of the boys is $12$ $years$ and that of the girls is $11$ $years$. If the average age of the school is $11$ $years$ and $9$ $months$,then the number of girls in the school is: