Evelyn gave a $3 tip to the person delivering her $15 pizza. What percent of the cost of the pizza was the tip that she paid?

The answer is .20 or 20 percent. Here is why, percents can be flipped so you can say “what is 3 percent of 15”. Well that would be 3*100=300/15 which gives you 20 and therefore you can say 0.20. Now to check your answer do 15 times 0.20 or 15 times 20 percent you will get three. Hopefully this helps!