Final answer:
To calculate the time difference between the first P-wave and the first S-wave, we need to know the velocity of these waves. Without that information, we cannot provide an exact answer.
Step-by-step explanation:
To calculate the time difference between the first P-wave and the first S-wave, we need to know the velocity of these waves. Without that information, we cannot provide an exact answer. However, based on the given context from previous questions, we can see that the speed of S-wave is around 2 km/s and the speed of P-wave is around 6 km/s. The time difference between these waves can be calculated using the formula:
Time difference = Distance / Speed
In this case, the distance is 500 km. Therefore, the time difference can be calculated as:
Time difference = 500 km / (6 km/s - 2 km/s)