The average weight of $3$ men $A, B$ and $C$ is $84 \,k g .$ Another man, $D,$ joins the group, and the average weight becomes $80\, kg .$ If another man, $E$, whose weight is $3 \,kg$ more than that of $D ,$ replaces $A$, then average weight of $B , C , D$ and $E$ becomes $79 \,kg$. The weight of $A$ is (in $kg$)
$70$
$72$
$75$
$80$
A batsman, in his $12^{th}$ innings, makes a score of $63$ runs and thereby increases his average score by $2.$ The average of his score after $12^{th}$ innings is
A club has $15$ men and $25$ women. The average age of men is $10\, years$ and the average age of women is $12 \,year.$ What is the average age of the whole club in $year$?
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 decreases by $Rs.\, 1 .$ Find the original expenditure of the mess in $Rs.$
The average weight of a class of $24$ students is $35 \,kg$. If the weight of the teacher is included the average rises by $400\, g.$ The weight of the teacher is (in $kg$)
The average of the first $100$ positive integers is