The average expenditure of a man for the first five months is $Rs. 120$ and for the next seven months is $Rs. 130$. His monthly average income in $Rs.$ if he saves $Rs. 290$ in that year,is

There are two groups $A$ and $B$ of a class,consisting of $42$ and $28$ students,respectively. If the average weight of group $A$ is $25 \, kg$ and that of group $B$ is $40 \, kg$,find the average weight of the whole class.

$A$ person travelled from one place to another at an average speed of $40 \, km/h$ and back to the original place at an average speed of $50 \, km/h$. What is his average speed in $km/h$ during the entire trip?

$A$ batsman scores $98$ runs in the $17^{\text{th}}$ match of his career. His average runs per match increases by $2.5$. What is his average before the $17^{\text{th}}$ match?

Mr. Patel walked $6 \, km$ to reach the station from his house,then he boarded a train whose average speed was $60 \, km/hr$ and thus he reached his destination. In this way,he took a total of $3 \, hours$. If the average speed of the entire journey was $32 \, km/hr$,then the average speed of walking is (in $km/hr$):

The average of certain first consecutive natural numbers is $20.5$. Find their sum.