The average of the price per $kg$ of rice at $10$ different places was $Rs.\, 4.85.$ After a week, the price per $kg.$ was increased by $20$ paise at $3$ places and decreased by $10$ paise at one place. The new average of price per $kg$ is in $Rs.$

Five years ago, the average age of $P$ and $Q$ was $15 \,year.$ Now, average age of $P , Q$ and $R$ is $20 \,year.$ What whould be the age of $R$ after $10$ $year$ in $year$ ?

The mean weight of $34$ students of a school is $42\, kg$. If the weight of the teacher be included, the mean rises by $400\, g.$ Find the weight (in $kg$) of the teacher.

The average of six numbers is $20 .$ If one number is removed, the average becomes $15 .$ What is the number removed ?

Visitors to a show were charged $Rs.\, 15$ each on the first day, $Rs.\, 7.50$ on the second day, $Rs.\, 2.50$ on the third day and total attendance on three days were in the ratio $2: 5: 13$ respectively. The average charge per person for the entire three days is (in $Rs.$)

The average salary of workers in $AMS$ careers is $Rs.\, 2,000$ , the average salary of faculty being $Rs. \,4,000$ and the management trainees being $Rs. \,$ $1,250 .$ The total number of workers could be