The average weight of $3 \operatorname{men} A, B$ and $C$ 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 average weight of $B, C, D$ and $E$ becomes $79 \,kg .$ The weight of $A$ is (in $kg$)
$70$
$72$
$75$
$80$
The average weight of a group of $20 \,boys$ was calculated to be $89.4\, kg$ and it was later discovered that one weight was misread as $78 \,kg$ instead of $87 \,kg.$ The correct average weight is (in $kg.$)
The average of marks of $28$ students in Mathematics was $50 .$ $8$ students left the school, then this average increased by $5 .$ What is the average of marks obtained by the students who left the school?
$19$ persons went to a hotel for a combined dinner party. $13$ of them spent $Rs.\, 79$ each on their dinner and the rest spent $Rs.\, 4$ more than the average expenditure of all the $19 .$ What was the total money spent by them.
The average salary of $20$ workers in an office is $Rs.\, 1900$ per $month.$ If the manager's salary is added, the average becomes $Rs.\,2000$ per $month.$ The manager's annual salary (in $Rs.$) is
The average of a collection of $20$ measurements was calculated to be $56\, cm .$ But later, it was found that a mistake had occurred in one of the measurements which was recorded as $64 \,cm ,$ but should have been $61 \,cm$. The correct average must be? (in $cm$)