The distance between Xiaoming and Xiaojun is 1800 meters. Xiaoming and Xiaojun start from home at the same time. Xiaoming walks 50 meters per minute, and Xiaojun walks 40 meters per minute. After a few minutes, the two meet.
小明和小军两家相距1800米，小明和小军同时从家出发，小明每分钟行50米，小军每分钟行40米，多少分钟后两人相遇．
<gadget id="calculator">40 + 50</gadget>
<output>90</output>

<gadget id="calculator">1_800 / 90</gadget>
<output>20</output>

<result>20</result>