4000 grams kilo means thousand
In a food web the energy is originated from the SUN.
Sound source is at rest, you are moving with velocity v, f = frequency, c = speed of sound:
f = f0(1 + v/c)
115 = 100(1 + v/343)
115 = 100 + 100v/343
15 = 100v/343
v = 15*343/100
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v = 51,45 m/s </span>