The average of $7$ numbers is $5$. If the average of the first six of these numbers is $4$,the seventh number is:

Find the average of all the numbers between $6$ and $34$ which are divisible by $5$.

The average of three numbers is $154$. The first number is twice the second and the second number is twice the third. The first number is

$3 \, \text{years}$ ago,the average age of a family of $5 \, \text{members}$ was $17 \, \text{years}$. With the birth of a new baby,the average age of the $6 \, \text{members}$ remains the same even today. Find the age of the new baby in years.

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 $Rs.$)

The average of $100$ observations was calculated as $35$. It was found later that one of the observations was misread as $83$ instead of $53$. The correct average is: (in $.7$)