An engineer must choose between two materials for an underground storage tank. A steel tank costs $219,000 and is expected to last 15 years. A fiberglass tank costs $299,000 and is expected to last 30 years. Neither tank has a salvage value at the end of its useful life. Determine the MARR below which the FRP tank is preferred. Express your answer in % (not a decimal) to the nearest 0.1%.

Answer is 6.9