A batch of cement, if the first batch of cement (2/9) is removed, if another 15 tons are removed, the ratio of the removed to the rest is 1:1, how many tons of this batch of cement originally?
一批水泥，第一次运走这批水泥的(2/9)，如果再运走15吨，则运走的与剩下的比是1：1，这批水泥原有多少吨？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 9</gadget>
<output>2/9 = around 0.222222</output>

<gadget id="calculator">(1/2) - (2/9)</gadget>
<output>5/18 = around 0.277778</output>

<gadget id="calculator">15 / (5/18)</gadget>
<output>54</output>

<result>54</result>