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

Two numbers $A$ and $B$ are such that the sum of $5 \%$ of $A$ and $4 \%$ of $B$ is $\frac{2}{3}$ of the sum of $6 \%$ of $A$ and $8 \%$ of $B$. The ratio $A:B$ is

One side of a square is increased by $30 \%$. To maintain the same area,the other side will have to be decreased by:

In an examination,$65 \%$ of students passed in Civics and $60 \%$ in History,while $40 \%$ passed in both of these subjects. If $90$ students failed in both History and Civics,then what is the total number of students?

On a test consisting of $150$ questions,Rita answered $40 \%$ of the first $75$ questions correctly. What per cent of the other $75$ questions does she need to answer correctly for her grade on the entire exam to be $60 \%$?

In Jamshedpur,only two newspapers,Dainik Jagran and Prabhat Khabar,are published. It is known that $25 \%$ of the city population reads Dainik Jagran and $20 \%$ reads Prabhat Khabar,while $8 \%$ reads both the newspapers. It is also known that $30 \%$ of those who read Dainik Jagran but not Prabhat Khabar look into advertisements,$40 \%$ of those who read Prabhat Khabar but not Dainik Jagran look into advertisements,and $50 \%$ of those who read both the newspapers look into advertisements. What is the percentage of the population who read an advertisement?