$1200$ boys and $650$ girls appeared in an examination. If $70 \%$ of boys and $40 \%$ of girls failed,find the approximate percentage of passed students.

$0.01$ is what percent of $0.1$?

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?

Peter could save $10 \%$ of his income. But two years later,when his income increased by $20 \%$,he could save the same amount as before. By what percentage has his expenditure increased?

$A$ shopkeeper marks the prices of his goods at $25 \%$ higher than the original price. After that,he allows a discount of $12 \%$. What profit or loss did he make?

If $37 \frac{1}{2} \%$ of a number is $45,$ then $87 \frac{1}{2} \%$ of the number will be: