Let A and B be two tuning forks, then frequency of A
nA = 256 Hz
Tuning fork b produces 6 beats with fork B.
∴ nB = nA ± n = 256 ± 6 = 250 or 262 Hz
∵Fork B produces 3 beat/s with the other fork (frequency 253 Hz), it is only possible when.
n3 = 250 Hz