To build a 10 km long road, 1.5 km was built in 3 days. According to this calculation, how many days will it take to complete the road? (Solve with ratio)
修一条10千米长的公路，3天修了1.5千米．照这样计算，修完这条公路要用多少天？(用比例解)
<gadget id="calculator">1.5 / 3</gadget>
<output>0.5</output>

<gadget id="calculator">10 / 0.5</gadget>
<output>20</output>

<result>20</result>