The average income of $A$ for $15$ days is $Rs. 70$. The average for the first five days is $Rs. 60$ and that for the last nine days is $Rs. 80$. $A$'s income for the sixth day is (in $Rs.$):

The average of $25$ results is $20$. The average of the first $12$ results is $15$ and that of the last $12$ results is $18$. Then,the $13^{th}$ result is:

Average of $a, b$ and $c$ is $11$; average of $c, d$ and $e$ is $17$; average of $e$ and $f$ is $22$ and average of $e$ and $c$ is $17$. Find out the average of $a, b, c, d, e$ and $f$?

The average of the first $25$ numbers is $10$ and the average of the next $25$ numbers is $12$. The average of all $50$ numbers is:

The average age of a group of $15$ students is $10 \, \text{years}$. When $5$ more students joined the group,the average age increased by $1 \, \text{year}$. If the average age of the $5$ new students is $x$,find the value of $x$ (in $\text{years}$).

The average of $5$ quantities is $6$. The average of three of them is $8$. What is the average of the remaining two quantities?