The average of $5$ quantities is $6 .$ The average of three of them is $8 .$ What is the average of remaining two quantities?
$2$
$5$
$9$
$7$
The average of $20$ numbers is $30$ and that of other $30$ numbers is $50 .$ What is the average of all the numbers.
The average weight of $10$ students is increased by half a $kg$ when one of the students weighing $50\, kg$ is replaced by a new student. Find out the weight of the new student.(in $kg$)
The average weight of $24$ students is $35\, kgs.$ If the weight of teacher is added the average increased by $400\, gms$. What is the weight of the teacher? (in $kg$)
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 diminishes by $Rs.\,1$ Find the actual expenditure of the mess. (in $Rs.$)
The average age of a family of $6$ members is $22\, years.$ If the age of the youngest member be $7\, years,$ then what was the average age of the family at the birth of the youngest member?