To build a road with a total length of 150 kilometers, and 60 kilometers were repaired in the first 20 days. According to this calculation, how many days will it take to complete the repair?
修一条公路，总长150千米，前20天修了60千米，照这样计算，还要多少天可修完？
<gadget id="calculator">150 - 60</gadget>
<output>90</output>

<gadget id="calculator">60 / 20</gadget>
<output>3</output>

<gadget id="calculator">90 / 3</gadget>
<output>30</output>

<result>30</result>