To build a canal, Team A can repair the full length (1/4) in 5 days, and Team B alone can complete the repair in 15 days. If the two teams work together, how many days can it be completed?
修一条水渠，甲队5天可以修全长的(1/4)，乙队单独修15天可以修完，如果两队合修，多少天可以修完？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / 5</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/20) + (1/15)</gadget>
<output>7/60 = around 0.116667</output>

<gadget id="calculator">1 / (7/60)</gadget>
<output>60/7 = around 8.571429</output>

<result>60/7 = around 8.571429</result>