$67 \%$ of $801 - 231.17 = ? - 23 \%$ of $789$

$A$ number increased by $22 \frac{1}{2} \%$ gives $98$. The number is

The population of a town is decreased by $20 \%$ and $25 \%$ in two successive years. What per cent population is decreased after two years?

The monthly income and monthly expenditure of a person were $₹ 13500$ and $₹ 9000$ respectively. In the next year,his income increased by $14 \%$ while his expenditure increased by $7 \%$. The percentage increase in his savings is: (in $\%$)

What percent of $7.2 \,kg$ is $18 \,g$?

In an examination,a candidate obtains $25\%$ marks and fails by $45$ marks,while another candidate obtains $46\%$ marks and passes by $15$ marks. What are the passing marks?