car travels from A to B at 60 km per hour and arrives in 4 hours. When returning, it only took 3 hours because the car was empty. How much more kilometers per hour did you travel when you returned than when you went?
一辆汽车从甲地开往乙地，每小时行驶60千米，4小时到达．返回时，因空车行驶，只用3小时．返回时每小时比去时多行多少千米？
<gadget id="calculator">4 / 3</gadget>
<output>4/3 = around 1.333333</output>

<gadget id="calculator">60 * (4/3)</gadget>
<output>80</output>

<gadget id="calculator">80 - 60</gadget>
<output>20</output>

<result>20</result>