Complete Question
An ambulance is driving towards the hospital at a velocity 94.0 km/h and emitting a steady 878-Hz sound from its siren. The sound reflects off the front of the hospital and is received by the same ambulance. In addition to it's own siren, the ambulance hears a shifted tone from the reflection at what frequency? The speed of sound on this day is 343 m/s
Answer:
The frequency is

Step-by-step explanation:
From the question we are told that
The velocity of the ambulance

The frequency emitted is

The illustration of the process is shown on the first uploaded image
The frequency at the hospital wall due to Doppler's effect is mathematically repented as
![f_1 = f_o [(v)/(v-v_o) ]](https://img.qammunity.org/2021/formulas/physics/college/q5nqpey5y8sdtzq5ul3gkcnua8fo0ry1qf.png)
Now as seen the frequency at the ambulance is mathematically represented as
![f = f_1 [(v+v_o)/(v) ]](https://img.qammunity.org/2021/formulas/physics/college/3w93v94ti5p7auaadpbuq4bkp40w8sp50p.png)
Now substituting for

![f = f_o [(v+v_o)/(v-v_o) ]](https://img.qammunity.org/2021/formulas/physics/college/fxujaiyyi26qmtc14818utsw45i9dmbttq.png)
Substituting value

