$A$ clerk received an annual salary of $Rs$ $3,660$ in the year $1975$. This was $20\%$ more than his salary in $1974$. What was his salary in $1974$?

The population of a town is $123,456,789$. It increases by $10\%$ during the first year,$20\%$ during the second year,and $30\%$ during the third year. What is the average percentage increase during the three years?

The present population of a town is $26010$. It increases annually at the rate of $2\%$. What was the population of the town two years ago?

If $60 \%$ of $A = 30 \%$ of $B$,$B = 40 \%$ of $C$ and $C = x \%$ of $A$,then the value of $x$ is:

$405$ toffees were distributed equally among children in such a way that the number of toffees received by each child is $20 \%$ of the total number of children. How many toffees did each child get?

Ram donated $4 \%$ of his income to a charity and deposited $10 \%$ of the rest in a bank. If now he has $Rs$ $8640$ left with him,then his income is