Amelia's car used 16 gallons to travel 656 miles. How many gallons of gas would she need to travel 533 miles?
If Amelia's car used 16 gallons to travel 656 miles, then the car's mileage is 656/16 = <<656/16=41>>41 miles per gallon
If the car's mileage is 41 miles per gallon, then Amelia would need 533/41 = <<533/41=13>>13 gallons to travel 533 miles. Answer: \boxed{13}.