It takes 15 days for team A to repair a canal alone, and 12 days for team B to repair it alone. Team A repairs 5 days first, and the rest is jointly repaired by teams A and B. How many days will it take to complete the repair?
修一条水渠，甲队单独修要用15天，乙队单独修要用12天，甲队先修了5天，剩下的由甲、乙两队合修，还要几天才能修完？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/15) * 5</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/15) + (1/12)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(2/3) / (3/20)</gadget>
<output>40/9 = around 4.444444</output>

<result>40/9 = around 4.444444</result>