It takes 3 hours for the car to go from A to B, and 4 hours to return. It is known that the car travels 12 kilometers per hour more than when it returns. How many kilometers are there between A and B?
汽车从甲地开往乙地去时用了3小时，返回时用了4小时．已知这辆汽车去时比返回时每小时多行12千米．甲、乙两地相距多少千米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/3) - (1/4)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">12 / (1/12)</gadget>
<output>144</output>

<result>144</result>