When both source and observer approach each other with a speed a equal to the half the speed of sound, then determine the percentage change in frequency of sound as detected by the listener.

Explanation

Source `overset((v)/(2))rarr overset((v)/(2))(larr)` Observer `n'=((v+(v)/(2))/(v-(v)/(2)))n=(((3)/(2)v)/((1)/(2))v)n=3n`
% change `= (n'-n)/(n)xx100 =(3n-n)/(n)xx100=(2n)/(n)xx100=200%`.