The average of nine numbers is $50$. The average of the first five numbers is $54$ and that of the last three numbers is $52$. Then the sixth number is?

The average weight of $5$ persons,sitting in a boat,is $38 \, kg$. If the average weight of the boat and the persons sitting in the boat is $52 \, kg$,what is the weight of the boat? (in $kg$)

Out of seven given numbers,the average of the first four numbers is $4$ and that of the last four numbers is also $4$. If the average of all the seven numbers is $3,$ then the fourth number is?

$A$ batsman has an average of $30$ runs in his $42$ innings. The difference between his maximum and minimum score is $100$. If these two innings are removed,his average for $40$ innings comes down to $28$. What is his minimum score?

The average of five consecutive positive integers is $n$. If the next two integers are also included,the average of all these integers will

The average age of $36$ students in a group is $14$ years. When the teacher's age is included, the average increases by $1$. What is the teacher's age in years?