The Speed of Sound Through the Ground Is About 6

Multiple Choice

The speed of sound through the ground is about 6.0 km/s while the speed of sound in air is 343 m/s.A very powerful explosion occurs some distance away and you feel the ground vibrate 60 seconds before you hear the sound of the explosion.How far away is the explosion?

A) 20 km
B) 22 km
C) 25 km
D) 27 km
E) 30 km