In an election between two candidates,one got $52 \%$ of the total valid votes. $25 \%$ of the total votes were invalid. The total number of votes were $8400$. How many valid votes did the other person get?

To attract more visitors,the zoo authority announces a $20 \%$ discount on every ticket,which costs $25 \ p$. For this reason,the sale of tickets increases by $28 \%$. Find the percentage of increase in the number of visitors.

An empty fuel tank of a car was filled with $A$ type petrol. When the tank was half-empty,it was filled with $B$ type petrol. Again when the tank was half-empty,it was filled with $A$ type petrol. When the tank was half-empty again,it was filled with $B$-type petrol. What is the percentage of $A$ type petrol at present in the tank?

$A$ number $x$ is $125 \%$ of $y$. To compute $y$,the number $x$ has to be multiplied by:

Aman gave $40 \%$ of the amount he had to Rohan. Rohan in turn gave one-fourth of what he received from Aman to Sahil. After paying $₹ 200$ to the taxi driver out of the amount he got from Rohan,Sahil now has $₹ 600$ left with him. How much amount did Aman have?

If $200 \%$ of a number is $90,$ then what is the $80 \%$ of that number?