Xiao Ming walks a certain distance at a constant speed. If he walks 0.5 kilometers more per hour, it will save (1/5) time. If he walks 0.5 kilometers per hour less, it will take 2.5 hours more. How many kilometers is this distance?
小明以匀速行走某一段路程，如果他每小时多走0.5公里，将节省(1/5)的时间，如果他每小时少走0.5公里，则需要多用2.5小时，那么这段路程有多少公里？
<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">1 / (4/5)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(5/4) - 1</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">0.5 / (1/4)</gadget>
<output>2</output>

<gadget id="calculator">2 - 0.5</gadget>
<output>1.5</output>

<gadget id="calculator">2.5 / 0.5</gadget>
<output>5</output>

<gadget id="calculator">2 * 1.5 * 5</gadget>
<output>15</output>

<result>15</result>