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## Homework Statement

When an earthquake occurs, two types of sound waves are generated and travel through the earth. The primary, or P, wave has a speed of about 7.87 km/s and the secondary, or S, wave has a speed of about 4.86 km/s. A seismograph, located some distance away, records the arrival of the P wave and then, 76.8 s later, records the arrival of the S wave. Assuming that the waves travel in a straight line, how far is the seismograph from the earthquake?

Pwave = 7.87km/s OR 7870m/s

Swave = 4.86km/s OR 4860m/s

## Homework Equations

I don't think there's an equation specifically for this, if there is, i haven't got it yet

## The Attempt at a Solution

I've figured out that when the pwave reaches the station it takes 76.8s for the swave to get there. So the distance at that point is 373.248km or 373248m. But i can't get the distance that it took before then.

Pwave--------------------------------------------| Station

Swave------------|_______________________| Station

x 373,248m

I tried to make it easier to understand, i can't find the distance "x", i know it traveled some distance before getting to the station i just don't know how to find that.

Someone help.

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