EcoRubber, Inc. manufactures the small rubberized squares that are being installed where tree roots, freezing weather, and snow removal have required sidewalk replacement or major repairs every 3 years. The state of Idaho spent $60,000 for a rubber sidewalk to replace broken concrete in a residential neighborhood lined with towering willow oaks. If a concrete sidewalk costs $28,000 and lasts only 3 years versus a 9-year life for the rubber sidewalks, what rate of return does this represent? The ROR is expected to be between 10 and 20%. Give the ROR value with at least one decimal place accuracy. Show all your work (no credits for the use of spreadsheet such as Excel).