Cheng Lin's home is 3,140 meters away from the school. She rides a bicycle home every day. The tire diameter of the bicycle is 50 cm. If the bicycle turns 80 times per minute, how long will it take Cheng Lin to get home?
程琳家离学校有3140米，她每天骑自行车回家，自行车的轮胎直径是50厘米，如果自行车每分钟转80圈，程琳多长时间可以到家？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * (1/2) * 80</gadget>
<output>125.6</output>

<gadget id="calculator">3_140 / 125.6</gadget>
<output>25</output>

<result>25</result>