A pile of coal was shipped in three days, 4 tons were shipped on the first day, the second day was the first day’s (9/8), and the second day accounted for (2/5) of the pile of coal. How many tons of coal?
一堆煤三天运完，第一天运了4吨，第二天运的是第一天的(9/8)，第二天运的占这堆煤的(2/5)，这堆煤有多少吨？
<gadget id="calculator">9 / 8</gadget>
<output>9/8 = around 1.125</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(9/8) / (2/5)</gadget>
<output>45/16 = around 2.8125</output>

<gadget id="calculator">4 * (45/16)</gadget>
<output>45/4 = around 11.25</output>

<result>45/4 = around 11.25</result>