Can someone PLZ help me

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

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

Your friend uses c=50p to find the total cost, c, for the people, p, entering a local amusement park what is the unit rate and what does it represent in the context of the situation?