For two new candles of the same length, it takes 2 hours to light all the thick candles and 1 hour to light all the thin candles. Light these two candles at the same time. 3 times. Find how long the candle has been lit.
两支同样长的新蜡烛，粗蜡烛全部点完要2小时，细蜡烛全部点完要1小时，同时点燃这两支蜡烛，到同时熄灭时，剩下粗蜡烛的长是剩下细蜡烛长的3倍．求蜡烛点燃了多少时间．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

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

<gadget id="calculator">3 * (1/60)</gadget>
<output>1/20 = around 0.05</output>

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

<gadget id="calculator">(1/20) - (1/120)</gadget>
<output>1/24 = around 0.041667</output>

<gadget id="calculator">2 / (1/24)</gadget>
<output>48</output>

<result>48</result>