The income of a company increases $20 \%$ per annum. If its income is $Rs$ $42664000$ in the year $1999$,what was its income in the year $1997$?

If $x$ $\%$ of $y$ is $100$ and $y$ $\%$ of $z$ is $200,$ then find a relation between $x$ and $z$.

$A$ person scores $45 \%$ of the total marks in the exam and still fails by $40$ marks. The passing percentage of the exam is $55 \%$. What is the maximum marks of the exam?

$0.06 \%$ of $250 \%$ of $1600$ is

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?

In an examination,$52 \%$ of the candidates failed in English and $42 \%$ failed in Mathematics. If $17 \%$ failed in both the subjects,then the percentage of candidates,who passed in both the subjects,was