Two cars depart from Beijing to a certain place at the same time. The truck travels 60 kilometers per hour and arrives in 15 hours. The passenger car travels 50 km per hour, how many hours later than the truck arrives.
两辆汽车同时从北京出发到某地，货车每小时行60千米，15小时到达．客车每小时行50千米，比货车晚多少小时到达．
<gadget id="calculator">60 * 15</gadget>
<output>900</output>

<gadget id="calculator">900 / 50</gadget>
<output>18</output>

<gadget id="calculator">18 - 15</gadget>
<output>3</output>

<result>3</result>