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## Homework Statement

I am having difficulty with this problem because I am not quite sure where to start.

A lecturer is demonstrating two-slit interference with sound waves. Two speakers are used 4.0 meters apart. The sound frequency is 325 Hz and the speed of sound is 343 m/s. Students sit in seats 4.5 meters away. What is the spacing between the location where no sound is heard because of destructive interference?

## Homework Equations

x <center>lamda

_ = <center>____ ????????????? (sorry these didn't line up too well)

L <center> d

## The Attempt at a Solution

I know full well that I'm supposed to show work, but the problem is that I don't know how to

*get started.*I tried using the equation that I showed above, using 4.0 as d and 4.5 as L, but then that leaves frequency and speed of sound, which don't fit in. I then tried v=f(lamda), which works partially, except they aren't asking for wave length in this problem as far as I know. I can't figure out if there's too much information in the problem, or if I'm just looking at the wrong equations. Any help would be appreciated. Thanks.