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 contribution of $5$ men to a fund is $Rs.\,35.$ $A$ sixth man joins and pays $Rs.\,35$ more than the resultant average of $6$ men. The total contribution of all the six men is (in $Rs.$)

$A$ library has an average of $510$ visitors on Sundays and $240$ on other days. The average number of visitors per day in a month of $30$ days beginning with a Sunday is:

The average of the squares of the first ten natural numbers is

$5$ members of a team are weighed consecutively and their average weight is calculated after each member is weighed. If the average weight increases by $1 \ kg$ each time,how much heavier is the last player than the first one? (in $kg$)

The average age of a group of $9$ students is $20\, \text{years}$. When $6$ more students joined the group,the average age falls by $2\, \text{years}$. The average age of the new students is: