Two engineering teams, A and B, jointly dig a 900-meter-long tunnel. Team A alone needs 30 days to complete the excavation, and team B can complete the task in 3 days (1/8). The two teams work from both ends of the tunnel at the same time. How many days can be completed?
甲、乙两个工程队合挖一条长900米的隧道，甲队单独挖需要30天完成，乙队3天可完成任务的(1/8)，两队同时从隧道两端施工，多少天可以完成？
<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/8) / 3</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">(1/30) + (1/24)</gadget>
<output>3/40 = around 0.075</output>

<gadget id="calculator">1 / (3/40)</gadget>
<output>40/3 = around 13.333333</output>

<result>40/3 = around 13.333333</result>