A mountain bike has a diameter of 60 cm. Xiao Hong rides this bike to a park 9,420 meters away from his home. If it turns 100 times per minute, how long does Xiao Hong need to ride?
一种山地车的直径是60厘米，小红骑这种车去距离他家9420米的公园玩，如果每分钟转100圈，那么小红需要骑多长时间？
<gadget id="calculator">3.14 * 0.6 * 100</gadget>
<output>188.4</output>

<gadget id="calculator">9_420 / 188.4</gadget>
<output>50</output>

<result>50</result>