Question

if 30 beats are produced in 1 second,the difference in frequencies between two sounds waves traveling through a medium along a common path at the same time must be

Answer 1

Beat are produced when two sounds of different frequency superimposed in the medium

Here beats are defined as number of maximum intensity that we heard during the superposition

So here we have

$f_{beat} = |f_1 - f_2|$

so difference of two frequency must be same as number of beats heard in 1 second

so here

$|f_1 - f_2| = 30 beats/s$