You are standing 2.5 {\rm m} directly in front of one of the two loudspeakers shown in the figure. They are 3.0 {\rm m} apart and both are playing a...

You are standing 2.5 {rm m} directly in front of one of the two loudspeakers shown in the figure. They are 3.0 {rm m} apart and both are playing a 686 {rm Hz} tone in phase. As you begin to walk directly away from the speaker, at what distances from the speaker do you hear a minimum sound intensity? The room temperature is 20 ^circ {rm C}.