Answer:
About 7 min.
Explanation:
Secondary waves travel at speeds between 1 km/s and 8 km/s.
Let’s split the difference and assume that the wave travel at 4.5 km/s. Then
[tex]\text{Time} = \text{2000 km} \times \frac{\text{1 s}}{\text{4.5 km}} = \text{440 s }= \textbf{7.4 min}[/tex]
