Physics of Frequency ...?

Question

You are flying in an ultra-light aircraft at a speed of 34.7 m/s. An eagle, whose speed is 19.7 m/s, is flying directly toward you. Each of the given speeds is relative to the ground. The eagle emits a shrill cry whose frequency is 3610 Hz. The speed of sound is 330 m/s. What frequency do you hear?

Answer 1

f(observed)= f(v/(v+v’)
f- actual frequency
v’ - relative speed
v – speed of sound in air


f(observed) = 3610 (330/(300+ 34.7 + 19.7))=
f(observed) = 3100Hz