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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 the S wave is about , and that of the wave is . A seismograph records and waves from an earthquake. The first P wave arrives 4 min before the first wave. Assuming the waves travel in a straight line, at what distance does the earthquake occur?

Let and have speeds of and , respectively. The and waves take and seconds to reach the position of the seismograph, respectively.

The speed of wave is given as

The speed of wave is given as

The first wave arrives before the wave.

Distance at which earthquake occur willbe,