One morning in winter, Li Ming and his father stepped on the snow one after the other along a circular track to run and exercise from the same starting point in the same direction. Dad took 50 centimeters each step, and Li Ming took 30 centimeters each step. The footprints on the snow overlapped from time to time. , ran down a lap, leaving a total of 1680 footprints, how many meters is a lap of this runway?
冬天的一个早晨，李明和他爸爸踏着雪一前一后沿着一个圆形跑道从同一起点朝同一方向跑步锻炼，爸爸每步50厘米，李明每步30厘米，雪地上脚印时有重合，一圈跑下来，一共留下了1680个脚印，这个跑道一圈是多少米？
<gadget id="calculator">5 / 5 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">30 * (1/10)</gadget>
<output>3</output>

<gadget id="calculator">5 / 3 / 10</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">30 * (1/6)</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">1_680 / 7</gadget>
<output>240</output>

<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">240 * 30 * (1/20)</gadget>
<output>360</output>

<result>360</result>