The average temperature for Monday, Tuesday, Wednesday and Thursday was $48^{\circ}$. The average temperature for Tuesday, Wednesday, Thursday and Friday was $52^{\circ} .$ If the temperature on Monday was $42^{\circ} .$ then the temperature on Friday was (in $degrees$)
$58$
$56$
$52$
$50$
Out of $30$ teachers of a school, a teacher of age $60$ $years$ retired. In his place another teacher of age $30$ $years$ was appointed. As a result, the mean age of the teachers will
The average of certain first consecutive even number is $101.$ Find their sum?
The average of the squares of of first ten natural numbers is
The average of husband, wife and their child $3\, years$ ago was $27\, years$ and that of wife and the child $5\, years$ ago was $20\, years.$ The present age of the husband is (in $years$)
The average revenue of $13$ consecutive years of a company $Rs.\, 70$ $\,lakhs.$ If the average of first $7 \,years$ is $Rs.\, 65$ $\,lakhs$ and that of last $7\, years$ is $Rs.\, 77$ $\,akhs,$ find the revenue for the $7^{th}$ $year.$ (Rs. in $lakh$)