There are two mosquito coils with different lengths and thicknesses. The short one can burn for 8 hours, and the long one can burn for a short time (1/2). Ignite the two mosquito coils at the same time. After 3 hours, their lengths are exactly equal, and they are not lit. Before, the short mosquito-repellent incense was much shorter than the long mosquito-repellent incense.
有两根长短粗细不同的蚊香，短的一根可燃8小时，长的一根可燃时间是短的(1/2)，同时点燃两根蚊香，经过3小时，它们的长短正好相等，未点燃之前，短蚊香比长蚊香短多少．
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

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