Given:Moe, Larry, and Curly stand in a line with a spacing of d = 1.60 m. Larry is 3.00 m in front of a pair of stereo speakers 0.800 m apart, as shown in the figure . The speakers produce a single-frequency tone, vibrating in phase with each other.
Question: What are the two lowest frequencies that allow Larry to hear a loud tone while Moe and Curly hear very little?
Answer in kHz.
Okay I don't where to start. A little help?