\(n' = n\,\left( {\frac{{v - ( - {v_0})}}{{v - {v_s}}}} \right) = n\,\left( {\frac{{v + {v_0}}}{{v - {v_s}}}} \right)\)
\( = 124\,\left[ {\frac{{330 + (72 \times 5/18)}}{{330 - (72 \times 5/18)}}} \right] = 140\, vibration/sec.\)
($c=$ હવામાં ધ્વનિનો વેગ)