"percent" means "per hundred" hundredths.
a)Move the decimal point two places to the right (0.505 to 50.5%)
b)Move the decimal point two places to the left (22.8 % to 0.228)
c) Depends on what resources you're allowed:
Use a favelet or bookmarklet in a web browser. These are bits of JavaScript that are used in place of a URL in the browser's favorites or bookmarks. Search using Google or Ask.com or visit
Bookmarklets - Calculator and Converter tools (you may end up converting to yards between meters and feet). Note that despite the similar names, Java and JavaScript are significantly different technologies.
Determine the conversion factor through research then use multiplication (calculator or even pencil and paper)
or
Use a printed conversion chart. A search engine can locate those, some of which can be printed out for offline use. There may be some available for photocopying (legal fair use if you only copy a few pages for yourself) in books located in your school or public library's research section.