She spent 12% on her books last semester. To find a percent, You take 360 and 3000 and turn them into a fraction (
) and then you take x and put it over 100 (represents 100%) (
)
You then cross multiply.
you multiply the 100 times the 360 and then you divide by 3000, giving you 12, which is your percent. This works for any percent problems, and is fast and easy.