In expressing a length $81.472 \, km$ as nearly as possible with three significant digits,find the percentage error?

If $25 \%$ of a number is subtracted from a second number,the second number reduces to its $5/6$. What is the ratio of the first number to the second number?

In a certain school,$20 \%$ of students are below $8$ years of age. The number of students above $8$ years of age is $\frac{2}{3}$ of the number of students of $8$ years age,which is $48$. What is the total number of students in the school?

Shruti decided to donate $12 \%$ of her salary to an orphanage. On the day of donation,she changed her mind and donated $Rs. 3150$,which was $75 \%$ of what she had decided earlier. How much is Shruti's salary?

What per cent of $\frac{2}{7}$ is $\frac{1}{35} ?$

Twelve percent of Kaushal's monthly salary is equal to sixteen percent of Nandini's monthly salary. Suresh's monthly salary is half that of Nandini's monthly salary. If Suresh's annual salary is $Rs$ $1.08$ Lakhs,what is Kaushal's monthly salary?