Two construction teams excavate a tunnel, construction team A excavates an average of 15m per day, and construction team B excavates an average of 12m per day. How many days will it take to complete this 270m long tunnel? (answer in two ways)
两个施工队开凿一条隧道，甲施工队平均每天开凿15m，乙施工队平均每天开凿12m．这条长270m的隧道需要多少天才能完工？(用两种方法解答)
<gadget id="calculator">15 + 12</gadget>
<output>27</output>

<gadget id="calculator">270 / 27</gadget>
<output>10</output>

<result>10</result>