There was a sudden power outage during dinner, and my mother lit two candles of different thicknesses. After a while, when the electricity came, my mother extinguished the two candles at the same time. It is known that the two candles are all new, it takes 2 hours to light all the thick candles, and 1 hour to light the thin candles. At first the two candles are the same length, but when they go out the thick candle is twice the length of the thin candle. How many minutes was the power outage?
吃晚饭时突然停电了，妈妈点上两只粗细不同的蜡烛，过一会儿，电来了，妈妈将两支蜡烛同时熄灭．已知两支蜡烛全是新的，粗蜡烛全部点完要2小时，细蜡烛要1小时．开始两根蜡烛一样长，熄灭时粗蜡烛却是细蜡烛长度的2倍．停电有多少分钟．
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">1 / 60</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">2 * (1/60)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / 120</gadget>
<output>1/120 = around 0.008333</output>

<gadget id="calculator">(1/30) - (1/120)</gadget>
<output>1/40 = around 0.025</output>

<gadget id="calculator">1 / (1/40)</gadget>
<output>40</output>

<result>40</result>