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?

Rice is now being sold at $Rs. 30$ per $kg$. During last month,its rate was $Rs. 26$ per $kg$. Find by how much percentage must a family reduce its consumption to keep the expenditure fixed?

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

If the given two numbers are respectively $7 \%$ and $28 \%$ of a third number,then what percentage is the first of the second?

Mr. Shamin's salary increases every year by $10 \%$ in June. If there is no other increase or reduction in the salary and his salary in June $2011$ was $Rs$ $22,385$,what was his salary in June $2009$?

In an examination,the percentage of students qualified to the number of students appeared from school $A$ is $70 \%$. In school $B$,the number of students appeared is $20 \%$ more than the students appeared from school $A$ and the number of students qualified from school $B$ is $50 \%$ more than the students qualified from school $A$. What is the percentage of students qualified to the number of students appeared from school $B$?