Elias buys a vintage concert shirt for $20 at a resale shop. He estimates that the shirt will increase in value by 15% per year. Which recursive formula can you use to find out how much (in dollars) the shirt will be worth in n years?

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min