The weight of a container alone is $25 \%$ of the container filled with a certain fluid. When some fluid is removed,the weight of the container and remaining fluid is $60 \%$ of the original total weight. What fractional part of the liquid has been removed?

$16 \frac{2}{3} \%$ of $600 \, \text{gm} - 33 \frac{1}{3} \%$ of $180 \, \text{gm}$

$A$ person's salary has increased from $Rs. 7200$ to $Rs. 8100$. What is the percentage increase in his salary (in $\%$)?

What percentage of numbers from $1$ to $70$ have squares that end in the digit $1$?

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?

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