To transport a pile of coal, it is planned to transport 150 tons per day, and the transportation will be completed in 20 days. In fact, 400 tons will be transported in 2 days. According to this calculation, how many days can the transportation be completed?
运一堆煤，计划每天运150吨，20天运完，实际2天就运了400吨，照这样计算，实际几天可以运完？
<gadget id="calculator">400 / 2</gadget>
<output>200</output>

<gadget id="calculator">20 / 200</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">150 * (1/10)</gadget>
<output>15</output>

<result>15</result>