One day there was a power outage, and two candles of the same length were lit in the room at the same time. The quality of the two candles was different. One could last for 3 hours, and the other could last for 5 hours. The remaining length is 3 times the length of the other. How many hours was the power outage?
某日停电，房间里同时点燃了两支同样长的蜡烛，两支蜡烛的质量不同，一支可以维持3小时，另一支可以维持5小时，当送电时吹灭蜡烛，发现其中一支剩下的长度是另一支长度的3倍．这次停电时间是多少小时．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">3 * (1/3)</gadget>
<output>1</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2 / (4/5)</gadget>
<output>5/2 = around 2.5</output>

<result>5/2 = around 2.5</result>