The length of a rectangle is increased by $30 \%$ and the breadth by $20 \%$. Then the perimeter of the rectangle will increase by what percent?

From the salary of an officer,$10 \%$ is deducted as house rent,$20 \%$ of the rest,he spends on conveyance,$20 \%$ of the rest he pays as income tax and $10 \%$ of the balance,he spends on clothes. If he is left with ₹ $15552$,find his total salary.

From a container having pure milk,$20 \%$ is replaced by water and the process is repeated thrice. At the end of the third operation,the milk is: (in $\%$ pure)

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

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

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 $60 \%$?