Question

15 is 375% of what number?

Answer 1

part = % * total

they give you part and %

Answer 2

total = 15/3.75

Answer 3

375 = 15/n
n=15/375

Answer 4

opps my bad, forgot
375 = 15/n * 100, it should be
15/3.75

Answer 5

See http://www.khanacademy.org/video/describing-the-meaning-of-percent?playlist=Developmental%20Math
and the videos after this one.