The distance between A and B is 180 meters. A car travels from A to B and plans to arrive in 4.5 hours. Due to the foggy weather, the actual travel time is 4 kilometers less than planned per hour. How long does it take to reach City B?
甲、乙两地相距180米，一辆汽车从甲地开往乙地，计划4.5小时到达．因大雾天气，实际每小时比计划少行4千米，实际多少小时到达乙城？
<gadget id="calculator">180 / 4.5</gadget>
<output>40</output>

<gadget id="calculator">40 - 4</gadget>
<output>36</output>

<gadget id="calculator">180 / 36</gadget>
<output>5</output>

<result>5</result>