The transport team transported a batch of relief materials to the Wenchuan disaster area. The original plan was to travel 60 kilometers per hour and reach it in 5 hours. Due to the serious damage to the road, the actual average hour was 20 kilometers less than the original plan. How many hours does it take to actually reach the disaster area?
运输队运送一批救灾物资到汶川灾区．原计划每小时行60千米，5小时可以到达．由于道路受损严重，实际平均每小时比原计划少行20千米．实际到达灾区需要多少小时？
<gadget id="calculator">60 * 5</gadget>
<output>300</output>

<gadget id="calculator">60 - 20</gadget>
<output>40</output>

<gadget id="calculator">300 / 40</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>