If $A$'s salary is $20\%$ higher than $B$'s,then how much percent is $B$'s salary less than $A$'s salary?

In an election between two candidates,one got $55 \%$ of the total valid votes,and $20 \%$ of the total votes were invalid. If the total number of votes polled was $7500$,what was the number of valid votes that the other candidate received?

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?

Milk contains $5 \%$ water. What quantity of pure milk should be added to $10$ litres of milk to reduce this to $2 \%$?

In a school there are $1500$ students,$44 \%$ of whom are girls. The monthly fee of each boy is $₹ 540$ and the fee of each girl is $25 \%$ less than that of a boy. What is the sum of the monthly fees of all the boys and girls?

Which number is $60 \%$ less than $80$?