Two people, A and B, are running on a runway with a circumference of 400 meters. Their respective speeds are constant. A runs 160 meters per minute, and B runs 140 meters per minute. They start from the same place at the same time and walk in the same direction. How long does it take? Can A catch up with B?
甲乙二人在周长为400米的跑道上跑步，各自的速度不变，甲每分钟跑160米，乙每分钟跑140米，他们从同一地点同时出发同向而行，那么经过多长时间甲能追上乙？
<gadget id="calculator">160 - 140</gadget>
<output>20</output>

<gadget id="calculator">400 / 20</gadget>
<output>20</output>

<result>20</result>