I'm doing exam review and am having trouble with this. Can someone please help explain it to me?

This is one of the questions:

Scores on a Test are worth 40 marks.

a) If a student scores at the 80th percentile, what is the students raw score?

b) In which percentile are the students who scored 30/40?

c) If a student scores in the 70th percentile, what did they get on the test?