In a water park, surface waves are generated in a large swimming pool and propagate at a speed of 0.2 m/s. A 5.0 m wall stands in the pool perpendicular to the direction of propagation of the waves and has an opening in its center. Using a wave profile device, you measure that every 30 seconds, 45 wave crests strike the wall. You also notice that no waves reach the opposite side of the swimming pool, 4.0 m away from the wall, at a position of 0.40 m from the point directly opposite the opening. However, waves do reach the opposite side everywhere within this distance. Determine the width of the wall opening.