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?

If the average of $m$ numbers is $n^{2}$ and that of $n$ numbers is $m^{2},$ then the average of $(m + n)$ numbers is

$A$ man spends $Rs. 1800$ monthly on an average for the first four months and $Rs. 2000$ monthly for the next eight months and saves $Rs. 5600$ a year. His average monthly income is (in $Rs.$)

The average weight of $25$ persons is increased by $1 \, kg$ when one man weighing $60 \, kg$ is replaced by a new person. What is the weight of the new person (in $kg$)?

The average speed of a train in the onward journey is $25\%$ less than that of the return journey. The train halts for one hour on reaching the destination. The total time taken for the complete to and fro journey is $17\, \text{hours}$,covering a distance of $800\, \text{km}$ (one way). The speed of the train in the onward journey is (in $\text{km/h}$):

The mean of $11$ numbers is $35$. If the mean of the first $6$ numbers is $32$ and that of the last $6$ numbers is $37$, then find the sixth number.