Master Li drove from A to B to deliver the goods. He stopped for half an hour for some reason 3 hours after departure. In order to deliver the goods on time, he drove 5 kilometers per hour and continued to drive for 4 hours to arrive at B on time. Ask for A and B The distance between the two places?
李师傅驾车从A地到B地送货，出发后3小时因故停车半小时，为了按时交货，他每小时多行5千米，继续行驶4小时恰好准时到达B地，求A、B两地距离？
<gadget id="calculator">4 / 0.5</gadget>
<output>8</output>

<gadget id="calculator">5 * 8</gadget>
<output>40</output>

<gadget id="calculator">3 + 0.5 + 4</gadget>
<output>7.5</output>

<gadget id="calculator">40 * 7.5</gadget>
<output>300</output>

<result>300</result>