What is the speed of the train based on sound wave frequency changes?

[qustudent88]

Homework Statement

A train whistle sounds. As the train approaches, a stationary observer near the track hears the whistle at a frequency of 500 hertz. As the train recedes the observer hears the whistle at a frequency of 450 hertz. what is the speed of the train? v (sound) = 343 m/s

Homework Equations

Fa = f/(1-v(train)/Vs(Sound))
Fr = f/(1+v(train)/Vs(Sound))

The Attempt at a Solution

Vtrain = 18.05

 

[astrorob]

I concur.