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?

$A, B, C$ and $D$ are four consecutive odd numbers and their average is $42$. What is the product of $B$ and $D$?

Average age of $15$ students of a class is $15 \text{ years}$. Out of these,the average age of $5$ students is $14 \text{ years}$ and that of the other $9$ students is $16 \text{ years}$. The age of the $15^{th}$ student is (in $\text{years}$):

The sum of five numbers is $260$. The average of the first two numbers is $30$ and the average of the last two numbers is $70$. What is the third number?

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

In the first $10$ overs of a cricket game,the run rate was only $3.2$. What should be the run rate in the remaining $40$ overs to reach the target of $282$ runs?