There is a ratio of $5:4$ between two numbers. If $40\%$ of the first number is $12$,then what would be $50\%$ of the second number?

In a college election between two candidates,one candidate got $55 \%$ of the total valid votes. $15 \%$ of the votes were invalid. If the total votes were $15,200$,what is the number of valid votes the other candidate got?

Christy donated $10 \%$ of his income to an orphanage and deposited $20 \%$ of the remainder in his bank. If he has now $Rs$ $7200$ left,what is his income?

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

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?

$6 \frac{1}{4} \%$ of $1600 + 12 \frac{1}{2} \%$ of $800$ equals