A laying team paves a road of 1500 meters, and paves 900 meters in the first 6 days. According to this calculation, it will take how many days to complete the task. (Solve with ratio)
一个铺设队铺一条1500米的公路，前6天铺了900米，照这样计算还需要铺多少天可以完成任务．(用比例解)
<gadget id="calculator">1_500 - 900</gadget>
<output>600</output>

<gadget id="calculator">900 / 6</gadget>
<output>150</output>

<gadget id="calculator">600 / 150</gadget>
<output>4</output>

<result>4</result>