The population of a town is decreased by $20 \%$ and $25 \%$ in two successive years. What per cent population is decreased after two years?

$23 \%$ of $8040 + 42 \%$ of $545 = ? \%$ of $3000$

In an election between two candidates,$60 \%$ of the voters cast their vote,out of which $4 \%$ of the votes were declared invalid. $A$ candidate received $7344$ votes,which were $75 \%$ of the total valid votes. Find the total number of votes enrolled in the election.

Two shopkeepers sell a radio of similar brand and type at the same list price of $₹ 1000$. The first allows two successive discounts of $20 \%$ and $10 \%$,and the second allows two successive discounts of $15 \%$ and $15 \%$. Find the difference in discounts offered by the two shopkeepers.

When the price of a product was decreased by $10 \%$,the number sold increased by $30 \%$. What was the effect on the total revenue (in $\%$)?

Rajesh spent $Rs. 44620$ on Deepawali shopping,$Rs. 32764$ on buying a computer,and the remaining $32\%$ of the total amount he had as cash with him. What was the total amount?