A car travels 600 kilometers from place A to place B, and travels 60 kilometers per hour. After driving for 3 hours, it speeds up and travels 80 kilometers per hour. How many hours will it take to complete the journey?
一辆汽车从甲地到乙地，全程600千米，每小时行60千米，行车3小时后加快速度，每小时行80千米，行完全程还需要几小时？
<gadget id="calculator">60 * 3</gadget>
<output>180</output>

<gadget id="calculator">600 - 180</gadget>
<output>420</output>

<gadget id="calculator">420 / 80</gadget>
<output>21/4 = around 5.25</output>

<result>21/4 = around 5.25</result>