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

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 monthly salary of $20$ employees in an organisation is $Rs.\, 1500$. If the manager's salary is added, then the average salary increases by $Rs.\,100.$ What is the manager's monthly (in $Rs.$)

Amitabh's average expenditure for the $January$ to $June$ is $Rs.\, 4200$ and he spends $Rs.\, 1200$ in $January$ and $Rs. \,1500$ in $July.$ The average expenditure for the month of $February$ to $July$ is (in $Rs.$)

The average of $n$ numbers $x_{1}, x_{2}, \ldots, x_{n}$ is $x$. Then, the value of $\sum \limits_{i=1}^{n}\left(x_{i}-\bar{x}\right)$ is equal to

The sum of the ages of father and son at present is $33\,years.$ Two years ago the product of their ages was $28 \,years.$ What is the age of the father and the son? (in $years$)