$16$ children are to be divided into two groups $A$ and $B$ of $10$ and $6$ children. The average percent marks obtained by the children of group $A$ is $75$ and the average per cent marks of all the $16$ children is $76 .$ What is the average per cent marks of children of group $B$ ?
$77 \frac{1}{3}$
$78 \frac{1}{3}$
$77 \frac{2}{3}$
$78 \frac{2}{3}$
The average age of $8$ men is increased by $2\, years.$ When $2$ of them, whose ages are $20\, years$ and $24 \,years$ respectively, are replaced by $2$ women. What is the average age of these two women ? (in $years$)
The average weight of $4$ men $A, B, C$ and $D,$ is $67\, kg.$ The $5^{th}$ man $E$ is included and the average weight decreases by $2 \,kg$. A is replaced by $F.$ The weight of $F$ is $4 \,kg$ more than $E$. Average weight deereases because of the replacement of $A$ and now the average weight is $64\, kg.$ Find the weight of $A ?$
The average marks of Sameer decreased by $1,$ when he replaced the subject in which he has scored $40 \,marks$ by the other two subjects in which he has just scored $23$ and $ 25$ marks respectively. Later he has also included $57$ marks of Computer Science, then the average marks increased by $2.$ How many subjects were there initially?
The average temperature from Monday to Thursday is $48^{\circ} C$ and from Tuesday to Friday is $52^{\circ} C$. If the temperature on Monday is $42^{\circ} C$, what was it on Friday? (in $^{\circ} C$)
The average of first three numbers is double of the fourth number. If the average of all the four numbers is $12,$ find the $4^{th}$ number.