For long range communication an elephant uses a low frequency rumble that is undetectable to human ears. One elephant can pick up another elephant's call from a distance of 10 km. The frequency of this rumble is about 13 Hz. How fast does the rumble travel?

Question

my teacher said the answer is 769.2 m/s im confused and have a test tomorrow.:(

Answer 1

The rumble is a sound, and sound travels at a speed of 343 m/s in air.
The answer that was given is more than twice the speed of sound. Since we already know the speed of sound, we can
only calculate the time required to travel 10km.

VT = 10,000 m
343T = 10,000