The average weight of $5$ persons,sitting in a boat,is $38 \, kg$. If the average weight of the boat and the persons sitting in the boat is $52 \, kg$,what is the weight of the boat? (in $kg$)

The sum of three consecutive odd numbers is $38$ more than the average of these numbers. What is the first of these numbers?

$A$ batsman has a certain average of runs for $12$ innings. In the $13^{th}$ innings,he scores $96$ runs,thereby increasing his average by $5$ runs. What is his average after the $13^{th}$ innings?

$5$ members of a team are weighed consecutively and their average weight is calculated after each member is weighed. If the average weight increases by $1 \ kg$ each time,how much heavier is the last player than the first one? (in $kg$)

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:

Out of $30$ teachers of a school,a teacher of age $60$ $years$ retired. In his place another teacher of age $30$ $years$ was appointed. As a result,the mean age of the teachers will