A truck travels 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 45 kilometers per hour. It arrives halfway earlier than the truck hours, find the distance between a and b.
一辆以每小时30千米的速度的卡车从a地至b地，出发一小时后，一辆轿车以每小时45千米的速度也从a地驶往b地，它比卡车早到半个小时，求a、b间的距离．
<gadget id="calculator">1 + 0.5</gadget>
<output>1.5</output>

<gadget id="calculator">45 - 30</gadget>
<output>15</output>

<gadget id="calculator">1.5 / 15</gadget>
<output>0.1</output>

<gadget id="calculator">30 * 0.1 * 45</gadget>
<output>135</output>

<result>135</result>