The average age of four brothers is $12 \, \text{years}$. If the age of their mother is also included, the average increases by $5 \, \text{years}$. The age of the mother (in $\text{years}$) is:

$A$ number,$x$,equals $80 \%$ of the average of $5, 7, 14$ and a number $y$. If the average of $x$ and $y$ is $26$,then the value of $y$ is:

The average of $6$ numbers is $3.95$. The average of two of them is $3.4$,while the average of the other two is $3.85$. What is the average of the remaining two numbers?

There are $6$ consecutive odd numbers in increasing order. The difference between the average of the squares of the first $4$ numbers and the last $4$ numbers is $64$. If the sum of the squares of the first and the last element is $178$,then the average of all the $6$ numbers is:

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:

Find the average of the following set of scores: $253, 124, 255, 534, 836, 375, 101, 443, 760$.