A car drives from place A to place B, travels 60 kilometers per hour, and arrives at place B in 4 hours. When it returns, it travels 20 kilometers per hour faster than before. How long does it take to arrive at place A?
一辆汽车从甲地开往乙地，每小时行60千米，4小时到达乙地，返回时，每小时比原来快20千米，返回时几小时到达甲地？
<gadget id="calculator">60 + 20</gadget>
<output>80</output>

<gadget id="calculator">4 / 80</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">60 * (1/20)</gadget>
<output>3</output>

<result>3</result>