Three motorcycles, fast, medium and slow, start from a place and chase an overloaded passenger car. Their speeds are 24 km/h, 20 km/h, and 19 km/h respectively. It takes the fast car to catch up with the overloaded car. 3 hours, it took 5 hours for the CRRC to catch up with the overloaded car, so how many hours did it take for the slow car to catch up with the overloaded car?
快、中、慢三辆摩托车从甲地出发，追赶一辆超载客车，它们的速度分别是24千米/时、20千米/时、19千米/时，快车追上超载车用了3小时，中车追上超载车用了5小时，那么慢车追上超载车用了多少小时？
<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<gadget id="calculator">24 * 3</gadget>
<output>72</output>

<gadget id="calculator">100 - 72</gadget>
<output>28</output>

<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">28 / 2</gadget>
<output>14</output>

<gadget id="calculator">24 - 14</gadget>
<output>10</output>

<gadget id="calculator">19 - 14</gadget>
<output>5</output>

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

<gadget id="calculator">10 * (3/5)</gadget>
<output>6</output>

<result>6</result>