A and B set off from A and B at the same time, and walk toward each other. When they meet, B walks the whole distance (1/4). When A arrives at B, B is still 18 kilometers away from A. Find the distance between A and B.
甲乙两人分别从A，B两地同时出发，相向而行，相遇时乙走了全程的(1/4)，当甲到达B地时乙离A点还有18千米．求AB两地之间的距离．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

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

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">18 / (2/3)</gadget>
<output>27</output>

<result>27</result>