Howww i have no idea how to do this

Your food costs are $5,500. your total food sales are $11,000. what percent of your food sales do the food costs represent?

Elizabeth claims that the fourth root of 2 can be expressed as 2^m since (2^m)^n = 2. find the values of m and n for the case where elizabeth's claim is true.

8. kelly wants to buy a magazine that is $25. later the magazine was marked up an additional 20%. what is the new price?