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)

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

In an examination,$65 \%$ of students pass in History and $55 \%$ of students pass in Hindi. If $5 \%$ of students fail in both subjects,what is the percentage of students who passed in both subjects?

$20 \%$ of $30 \%$ of $20 \%$ of $₹ 850$ is:

In an examination,it is required to multiply a number by $7$,but by mistake,a student divides it by $7$. What is the error percentage?

Mr. Giridhar spends $50 \%$ of his monthly income on household items. Out of the remaining,he spends $50 \%$ on transport,$25 \%$ on entertainment,and $10 \%$ on sports. If the remaining amount of $RS. 900$ is saved,what is Mr. Giridhar's monthly income?