$50\%$ of $184$ is the same as:

A housewife saved Rs. $2.50$ in buying an item on sale. If she spent Rs. $25$ for the item, approximately how much per cent did she save in the transaction?

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

A student secures $90\%$, $60\%$ and $54\%$ marks in test papers with $100$, $150$ and $200$ respectively as maximum marks. The percentage of his aggregate is: