It takes three days to transport a pile of coal. On the first day, 240 tons are transported, and the second day transports 20% more than the first day. The ratio of the coal tons transported on the second day to the third day is 9:5 ． How many tons is this pile of coal?
三天要运完一堆煤，第一天运了240吨，第二天运的比第一天多20%，第二天和第三天所运的煤的吨数的比是9：5．这堆煤共有多少吨？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">240 * (6/5)</gadget>
<output>288</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">288 * (5/9)</gadget>
<output>160</output>

<gadget id="calculator">240 + 288 + 160</gadget>
<output>688</output>

<result>688</result>