One day there was a power outage and two candles of different thicknesses and equal lengths were lit in the room. The thick one could burn for 5 hours, and the thin one could burn for 3 hours. The length is three times the length of the thin one, what is the power outage time?
某日停电房间里点燃了粗细不同长度相等的两个蜡烛，粗的那根可以燃5小时，细的那根可以燃烧3小时，来电后同时熄灭两根蜡烛，发现粗的那根剩下的长度是细的那根的长度的3倍，问停电时间是多少？
<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">(1/3) * 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>