Help with percents markups and markdowns

[Koiloverlol]

i dont know if this in teh right place but I have to do this and im confused a little bit i got the first 1 and i think i got the second one.

 

[tkhunny]

Please demonstrate. Keep in mind for each problem, the given percent is a percent of what?

Quiz. Start with 100. Now, subtract 10% of that. Finally, add 10% of that. Where do you end up?