There is a highway to be repaired, and it takes 20 days for engineering team A to complete the repair alone, and 30 days for engineering team B alone. After 3 days of joint repair, engineering team B will be transferred away for other tasks, and engineering team A will complete the remaining tasks alone. How many more days?
有一条公路要修，甲工程队单独修需要20天完成，乙工程队单独需要30天，两队合修3天后，乙工程队另有任务调走，余下的任务由甲工程队单独完成，还需要几天？
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/20) + (1/30)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 3</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(3/4) / (1/20)</gadget>
<output>15</output>

<result>15</result>