In the first $30$ overs of a cricket match,the run rate was $5.2 \text{ runs/over}$. What is the required run rate in the remaining $20$ overs to reach the target of $280$ runs?

Of the three numbers whose average is $60$,the first is one-fourth of the sum of the others. The first number is

The average of $6$ numbers is $8$. What is the $7^{th}$ number so that the average becomes $10$?

The average of $3$ numbers is $22$. If the first number is $\frac{3}{8}$ of the sum of the other two numbers,what is the first number?

$A$ cricketer had a certain average of runs for his $64$ innings. In his $65^{th}$ innings,he is bowled out for no score on his part. This brings down his average by $2$ runs. What is his new average of runs?

The average of $6$ observations is $12$. $A$ new seventh observation is included and the new average is decreased by $1$. The seventh observation is