Xiao Wang starts from the county town to Wangzhuang on foot and travels 5 kilometers per hour. Xiao Li starts from Wangzhuang by bicycle and walks towards Xiao Wang at the same time, traveling 15 kilometers per hour. They meet each other after 2 hours. How many kilometers is Wangzhuang from the county seat?
小王步行从县城出发去王庄，每小时行5千米，小李骑车从王庄出发，与小王同时相向而行，每小时行15千米，经过2小时相遇．王庄离县城有多少千米？
<gadget id="calculator">5 + 15</gadget>
<output>20</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>