The average weight of three boys $A, B$ and $C$ is $54 \frac{1}{3} \,kg,$ while the average weight of three boys $B , D$ and $E$ is $53 \,kg .$ What is the average weight of $A , B , C , D$ and $E$ ?(in $kg$)

The average age of four brothers is $12 \,year.$ If the age of their mother be also included, the average is increased by $5\, year.$ The age of the mother (in $years$) is

The average age of a family of $6 \,members\, 4 \,year$ ago was $25 \,years.$ Mean while a child was born in this family and still the average age of the whole family is same today. The present age of the child is in $years$ $?$

There are two groups $A$ and $B$ of a class, consisting of $42$ and $28$ students, respectively. If the average weight of group $A$ is $25 \,kg$ and that of group $B$ is $40 \,kg ,$ find the average weight of the whole class.

The average of first $46$ natural number is

The average age of a man and his two twin born on the same day is $30 \,year.$ The ratio of the ages of father and one son is $5: 2,$ what is the father's age in $year?$