April 20, 2013 was Saturday, at around 8:00 in the morning, the students of a middle school earthquake interest group in Xi'an suddenly discovered that the seismograph in the science and technology laboratory had P-wave and S-wave earthquake off-time records. After calculating the ratio of P wave to S The wave arrives as early as 125 seconds. We know that during an earthquake, P waves and S waves are sent out from the source at the same time. The propagation speed of P waves is 6 km/s, and the propagation speed of S waves is 3 km/s. Please estimate, About how many kilometers is the epicenter of this earthquake from Xi'an?
2013年4月20日是星期六，早上8点左右，西安某中学地震兴趣小组的同学们突然发现科技实验室的地震记录仪有P波和S波的地震断时记录，经过测算P波比S波早到125秒，我们知道地震时，从震源同时发出P波和S波，P波的传播速度是6千米/秒，S波的传播速度是3千米/秒，请你估计一下，这次地震的震源距离西安大约有多少千米？
<gadget id="calculator">6 - 3</gadget>
<output>3</output>

<gadget id="calculator">3 * 125</gadget>
<output>375</output>

<result>375</result>