A truck drives from point A to point B at a speed of 30 kilometers per hour. One hour after departure, a car also drives from point A to point B at a speed of 50 kilometers per hour, arriving half an hour earlier than the truck B land. Find the distance between A and B.
一辆卡车以每小时30千米的速度从A地驶向B地，出发一小时后，一辆轿车以每小时50千米的速度也从A地驶向B地，比卡车早半小时到达B地．求A、B两地之间的距离．
<gadget id="calculator">1 + 0.5</gadget>
<output>1.5</output>

<gadget id="calculator">50 - 30</gadget>
<output>20</output>

<gadget id="calculator">1.5 / 20</gadget>
<output>0.075</output>

<gadget id="calculator">30 * 0.075 * 50</gadget>
<output>112.5</output>

<result>112.5</result>