A car is driving from place A to place B. It is planned to travel 90 kilometers per hour, and it can be reached in 4 hours. Due to the change of weather, the actual travel time is 15 kilometers less than the original plan, how many hours did the travel actually take? Use ratios to solve.
一辆汽车从甲地开往乙地，计划每小时行90千米，4小时可以到达．由于天气变化，实际每小时比原计划少行15千米，实际行了几小时？用比例解决．
<gadget id="calculator">90 * 4</gadget>
<output>360</output>

<gadget id="calculator">90 - 15</gadget>
<output>75</output>

<gadget id="calculator">360 / 75</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>