In a class,$70 \%$ of the students read Hindi,$40 \%$ of the students are boys,and $20 \%$ of the girls do not read Hindi. What percentage of boys read Hindi?

In an entrance examination,Ritu scored $56\%$ marks,Smita scored $92\%$ marks,and Rina scored $634$ marks. The maximum marks of the examination are $875$. What are the average marks scored by all the three girls together?

Express $\frac{7}{8}$ as a percentage.

If $35 \%$ of $A$'s income is equal to $25 \%$ of $B$'s income,then the ratio of $A$'s income to $B$'s income is

$A$ man spends $15 \%$ of his income. If his expenditure is $Rs$ $75,$ his income (in rupees) is:

In a certain quantity of ghee, $60 \%$ is pure ghee and $40 \%$ is vanaspati. If $10 \text{ kg}$ of pure ghee is added, the concentration of vanaspati ghee becomes $20 \%$. What was the original quantity (in $\text{ kg}$)?