Two teams, A and B, are building a 1,800-meter-long canal between village A and village B. Team A builds 42 meters a day, and team B builds 48 meters a day. If the two teams start work from villages A and B at the same time, how many days will it take to complete the canal?
甲乙两队在A村和B村之间修一条长1800米的水渠，甲队每天修42米，乙队每天修48米．如果两队分别从A、B两村同时开工，修完这条水渠需要几天？
<gadget id="calculator">42 + 48</gadget>
<output>90</output>

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

<result>20</result>