Three year ago, the average age of a family of five members was $27 \,year.$ The present average age is also $27 \,year$ after the inclusion of a child into the family. Find the age of the child in $year$ ?
$16$
$12$
$24$
$20$
The average of prime numbers between $1$ and $20$ is
The average weight of $100$ students is $32\, kg$. The average weight of first $49$ students is $30\, kg$ and that of last $50$ students is $34\, kg$. What is the weight (in $kg$ ) of the $50^{ th }$ student ?
The average weight of $5$ persons, sitting in a boat, is $38 \,Kg$. If the average weight of the boat and the persons sitting in the boat is $52 \,Kg$, what is the weight of the boat? (in $kg$)
The average of first nine prime numbers is
Average age of $5$ boys is $16$ $year$ of which that of $4$ boys is $16\, year\, 3\, months.$ The age of the $5^{th}$ boy is