The average of $6$ observations is $12$. $A$ new seventh observation is included and the new average is decreased by $1$. The seventh observation is

The average of three consecutive odd numbers is $52$ more than $\frac{1}{3}$ of the largest of these numbers. What is the smallest of these numbers?

The average of the first $9$ integral multiples of $3$ is

The average of two numbers $A$ and $B$ is $20,$ that of $B$ and $C$ is $19,$ and that of $C$ and $A$ is $21.$ What is the value of $A?$

What was the average daily expenditure in $Rs.$ of a man in $1999$ who spent $Rs. \, 76535$ in the first half of the year and $Rs. \, 88165$ in the second half?

$16$ children are to be divided into two groups $A$ and $B$ of $10$ and $6$ children. The average percent marks obtained by the children of group $A$ is $75$ and the average percent marks of all the $16$ children is $76$. What is the average percent marks of children of group $B$?