Monthly incomes of $A$ and $B$ are in the ratio of $4:3$ and their expenses bear the ratio $3:2.$ Each of them saves $\mathrm{Rs}.6,000$ at the end of the month, then the monthly income of $A$ is _____.

The average of $18$ observations is recorded as $124$. Later it was found that two observations with values $64$ and $28$ were entered wrongly as $46$ and $82$. Find the correct average of the $18$ observations.

The average age of four boys, five years ago was $9$ years. On including a new boy, the present average age of all the five is $15$ years. The present age of the new boy is _____.

The population of a town is $15000$. If the number of males increases by $8\%$ and that of females by $10\%$, then the population would increase to $16300$. Find the number of females in the town.