What is the average of all numbers between $100$ and $200$ which are divisible by $13\, ?$
$147.5$
$145.5$
$143.5$
$149.5$
In a class, there are $20$ boys whose average age is decreased by $2$ $months,$ when one boy aged $18\, years$ in replaced by a new boy. The age of the new boy is
The average monthly salary of $20$ employees in an organisation is $Rs.\, 1500$. If the manager's salary is added, then the average salary increases by $Rs.\,100.$ What is the manager's monthly (in $Rs.$)
If the mean of $a, b, c$ is $M$ and $a b+b c+c a=0,$ then the mean of $a^{2}, b^{2}, c^{2}$ is
Sum of eight consecutive numbers of Set $A$ is $376$ What is the sum of $5$ consecutive numbers of another set if its minimum number is $15$ ahead of average of Set $A ?$
A family consists of grand parents, parents and three grand children. The average age of the grand parents is $67\, years,$ that of the parents is $35\, years$ and that of the grand children is $6 \,years.$ What is the average age of the family? (in $years$)