The passenger car and the freight car depart from A and B respectively and meet at a distance of 10 kilometers from the midpoint. It is known that the passenger car takes 4 hours to complete the journey, and the truck takes 3 hours to complete the journey. How many kilometers are there between A and B?
客车与货车分别从A、B两地相对开出，在距中点10千米处相遇．已知客车行完全程需要4小时，货车行完全程需要3小时．A、B两地相距多少千米？
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">20 / (1/4)</gadget>
<output>80</output>

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

<gadget id="calculator">80 + 60</gadget>
<output>140</output>

<result>140</result>