1. The problem statement, all variables and given/known data Find the speed of a car if the tone of the horn drops by 36 percent as it passes you. The speed of sound is 340 m/s. Answer in units of km/h. 2. Relevant equations f'=f(v/(v-v_source)) solce for v source. 3. The attempt at a solution I thought I would just set .36f = f (340/(340-x)) and solve for x (x= -604.4) this is not the right answer.