sarah work at a concession stand for 2 hours and erans 22.50$, but if she works for 4 hours she earns $45. what is the rate of change

The area of a square floor on a scale drawing is 64 square centimeters, and the scale drawing is 1 centimeter: 3 ft. what is the area of the actual floor? what is the ratio of the area in the drawing to the actual area? the area of the actual floor is square feet. the ratio of the area in the drawing to the actual area is 1 square centimeter: square feet.