Ineed on this equation. i've seen someone post the formula on how to get the correct answer, but not the reasons behind why they used that particular method. if someone could me, it would be greatly appreciated. here's the problem:

at a movie rental machine, the movies rent for $3.00, except on tuesdays, when they rent for $0.49. approximately what percent of the regular cost is saved by renting a movie on a tuesday?