After replacing an old member by a new member, it was found that the average age of five members of a club is the same assit was $3 \,year$ ago. The difference between the ages of the replaced and the new member is ? (in $year$)

The average of $8$ numbers is $20 .$ The average of first two numbers is $15 \frac{1}{2}$ and that of next three is $21 \frac{1}{3}$. If the sixth number is less than the seventh and eighth numbers by $4$ and $7$ respectively, then the eighth number is

A student finds the average of $10,2$ digit numbers. If the digits of one of the number is interchanged, the average increases by $3.6 .$ The difference between the digits of the $2 -$digit numbers is

Average weight of $3 \,cm$ men $A , B , C$ is $84 \,kg$. Another man $D$ joins the group and the average now becomes $80 \,kg$. If another man $E$ whose weight is $3 \,kg$ more than that of $D$ replaces $A$ then the averageweight of $B , C , D$ and $E$ becomes $79\, kg .$ The weight of $A$ in $kg$ is

The average weight of $3$ person is $65 \,kg$. If a fourth person having a weight of $45 \,kg$ joins the group, what is the average weight of the group ? (in $kg$)

The average of $5$ consecutive integers starting with $m$ is $n$. What is the average of $6$ consecutive integers starting with $( m +2) ?$