The average marks obtained by $40$ students of a class is $86$. If the $5$ highest marks are removed,the average reduces by $1$ mark. The average marks of the top $5$ students is

The average age of a man and his two twin sons,born on the same day,is $30 \, \text{years}$. The ratio of the ages of the father and one son is $5:2$. What is the father's age in $\text{years}$?

The average of $50$ numbers is $38$. If two numbers,namely,$45$ and $55$ are discarded,what is the average of the remaining numbers (in $.5$)?

$12 \%$ of Kaushal's monthly salary is equal to $16 \%$ of Nandini's monthly salary. Suresh's monthly salary is half that of Nandini's monthly salary. If Suresh's annual salary is $Rs.\, 1.08$ lakhs,what is Kaushal's monthly salary in $Rs.$?

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 of runs scored by a cricketer in his $99$ innings is $99$. How many runs will he have to score in his $100^{\text{th}}$ innings so that his average of runs in $100$ innings may be $100$?