A certain construction site bought a batch of cement and shipped it out in three days. On the first day (3/10) of the total amount was shipped, on the second day (4/15) of the total amount was shipped, and on the third day more than 40 bags were shipped on the first day. How many bags of this batch of cement are there?
某建筑工地买来一批水泥，三天运完．第一天运来总数的(3/10)，第二天运来总数的(4/15)，第三天比第一天多运40袋，这批水泥共有几袋？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">1 - (3/10) - (4/15) - (3/10)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">40 / (2/15)</gadget>
<output>300</output>

<result>300</result>