Out of three numbers,the first is twice the second and is half of the third. If the average of the three numbers is $56$,the three numbers in order are

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 of $n$ numbers $x_{1}, x_{2}, \ldots, x_{n}$ is $\bar{x}$. Then,the value of $\sum_{i=1}^{n}(x_{i}-\bar{x})$ is equal to

The average age of a board of directors of a company,having $10$ directors,was $48$ years. Coincidentally,when a director aged $53$ resigned from the board,another director died on the same day. $A$ new director aged $34$ joined the board. Next year in the same month,the average age of all the $9$ directors was found to be $46$ years. The age of the late (i.e.,dead) director at the time of his death was (in years):

On $24^{\text{th}}$ May,$2008$,the maximum temperatures of Delhi,Kolkata,and Mumbai were recorded as $35^{\circ}C$,$33^{\circ}C$,and $34^{\circ}C$ respectively. What was the maximum temperature of Chennai so that the average maximum temperature of those four cities would be $35^{\circ}C$ (in $^{\circ}C$)?

$A$ group of boys has an average weight of $36 \,kg$. One boy weighing $42 \,kg$ leaves the group and another boy weighing $30 \,kg$ joins the group. If the average now becomes $35.7 \,kg$,then how many boys are there in the group?