The two siblings were playing in a circular flower garden with a circumference of 600 meters. They walked around the pool from the same place with their backs at the same time. The older sister walked 60 meters per minute. When they met for the first time in 6 minutes, they asked the younger brother how many meters per minute they walked.
姐弟二人在周长为600米圆形花圃边玩，从同一地点同时背向绕水池行走，姐姐每分钟走60米，6分钟第一次相遇，问弟弟每分钟走多少米？
<gadget id="calculator">600 / 6</gadget>
<output>100</output>

<gadget id="calculator">100 - 60</gadget>
<output>40</output>

<result>40</result>