Out of four numbers,the average of the first three is $16$ and that of the last three is $15$. If the last number is $20$,then the first number is:

The batting average for $40$ innings of a cricketer is $50$ runs. His highest score exceeds his lowest score by $172$ runs. If these two innings are excluded,the average of the remaining $38$ innings is $48$ runs. The highest score of the player is

The average annual income (in $Rs.$) of certain agricultural workers is $S$ and that of other workers is $T$. The number of agricultural workers is $11$ times that of other workers. Then the average annual income (in $Rs.$) of all the workers is

Nine friends have a dinner in a hotel. Eight of them spent $Rs. 12$ each on their meals and the ninth spent $Rs. 16$ more than the average expenditure of all the nine. Find out the total money in $Rs.$ spent by them?

The average age of $5$ sisters is $20 \, \text{years}$. If the age of the youngest sister is $4 \, \text{years}$,what was the average age of the group of sisters at the time of the birth of the youngest sister?

The daily earnings of a taxi driver during a week are: $Rs. 60, Rs. 65, Rs. 70, Rs. 52.50, Rs. 63, Rs. 73,$ and $Rs. 68$. What is his average daily earning for the week (in $.50$)? (in $Rs.$)