A pile of coal burns 50% of the total amount, and another 50 tons are brought in. At this time, the tonnage of coal in storage is 2/3 of the original total amount. How many tons does this pile of coal originally have?
一堆煤，烧掉了总数的50%，又运进来50吨，这时存煤吨数是原来总数的(2/3)，这堆煤原来有多少吨？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/3) - (1/2)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">50 / (1/6)</gadget>
<output>300</output>

<result>300</result>