A pile of coal, 20% of the pile of coal is used for the first time, and 290 kg is used for the second time. At this time, the remaining coal is 10 kg more than half of the original pile of coal. Find the total number of kilograms of the original pile of coal ?
一堆煤，第一次用去这堆煤的20%，第二次用去290千克，这时剩下的煤比原来这堆煤的一半还多10千克，求原来这堆煤共有多少千克？
<gadget id="calculator">10 + 290</gadget>
<output>300</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">300 / (3/10)</gadget>
<output>1_000</output>

<result>1_000</result>