A theme park creates a new kind of water wave pool with large waves caused by constructive interference. There are two wave generators in phase with each other along either side of a pool that is 24.0 m wide. A swimmer that is 9.0 m from one generator and 14.0 m from the other notices that she is in a region with almost no wave amplitude, but there are large-amplitude waves on either side of her. What is the longest wavelength that will produce this interference pattern?
Express your answer to three significant figures and include appropriate units.