To build a road with a total length of 12km, 0.72km was repaired 3 days before the start of construction. According to this calculation, how many days will it take to complete the road?
修一条全长12km的公路，开工前3天修了0.72km，照这样计算，修完这条路还要多少天？
<gadget id="calculator">0.72 / 3</gadget>
<output>0.24</output>

<gadget id="calculator">12 / 0.24</gadget>
<output>50</output>

<gadget id="calculator">50 - 3</gadget>
<output>47</output>

<result>47</result>