Since the water company laid a 1400m long water supply pipeline, 15% of the total length was laid in the first 3 days. According to this calculation, how many days will it take to complete the pipeline? (Solve with ratio)
自水公司铺设一条长1400m的供水管道，前3天铺了全长的15%，照这样计算，铺完管道一共要多少天？(用比例解)
<gadget id="calculator">1_400 * 3</gadget>
<output>4_200</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1_400 * (3/20)</gadget>
<output>210</output>

<gadget id="calculator">4_200 / 210</gadget>
<output>20</output>

<result>20</result>