Two trucks travel at the same speed. they are far apart on adjacent lanes and approach each other essentially head-on. one driver hears the horn of the other truck at a frequency that is 1.05 times the frequency he hears when the trucks are stationary. if the speed of sound is 344 m/s, at what speed is each truck moving?

this is how i worked it out but i got it wrong..

f=1.05hertz
1.05*f1=f1 (344+v1) / (344-v1)

(344-v1)*1.05 = (344+v1)
361.2-1.05v1= (344+v1)
361.2-344= 17.2
17.2=1.05v1
16.4m/s