I need some help getting started on this one: Sound waves of frequency 582 Hz enter a window 1.3m wide. The window is in the exact center of one wall of a theater 24m by 12m. The window is 12m from the opposite wall, along which is a row of seats occupied by people. The theater is acoustically prepared to prevent the reflection of sound waves, and the speed of sound is 330 m/s. Two people, on each side of a line directly in front of the window, in the row along the wall hear no sound. What minimum distance are they from each other?