Earthquakes generate sound waves inside the earth. Unlike a gas, the earth can experience both transverse (S) and longitudinal (P) sound waves. Typically the speed of S wave is about `4.0 km s^-1` and that of P wave is `8.0 km s^-1`A seismograph records Pand Swavesfrom an earthquake. The first Pwave arrives 4 min before the first S wave. Assuming the waves travel in straight line, at what distance does the earthquake occur ?