A warehouse originally had 100 tons of goods, but 30 tons were shipped away. What percentage of the mass of the original goods is the mass of the transported goods? A barrel of oil is used up in two days, 40% of the total amount is used on the first day, and what percentage of the total amount is used on the second day?
某仓库原有货物100吨，运走了30吨．运走的货物质量占原有货物质量的百分之几？一桶油两天用完，第一天用了总量的40%，第二天用了总量的百分之几？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>