Krishnamurthy earns $₹ 15000$ per month and spends $80 \%$ of it. Due to pay revision,his monthly income has increased by $20 \%$ but due to price rise,he has to spend $20 \%$ more. His new savings are

In two successive years,$80$ and $60$ students of a school appeared at the final examination,of which $60 \%$ and $80 \%$ passed respectively. The average rate of students passed (in percent) is

The average monthly salary of all the employees in a factory is $Rs$ $8840$. If the average salary of all the officers is $Rs$ $15000$ and that of the remaining employees is $Rs$ $8000$,then what is the percentage of the officers among the employees?

Two numbers are $50 \%$ and $80 \%$ less than a third number. By what percentage must the second number be increased to make it equal to the first number?

Two numbers are respectively $20 \%$ and $30 \%$ less than a third number. What is the second number as a percentage of the first?

The population of a town is $123,456,789$. It increases by $10\%$ during the first year,$20\%$ during the second year,and $30\%$ during the third year. What is the average percentage increase during the three years?