A bus travels from City A to City B at a speed of 36 kilometers per hour. After 2 hours, a van travels from City B to City A at a speed of 54 kilometers per hour. The bus meets the van at 9 km from the midpoint of A and B. How many miles is the distance between city A and city B?
一辆大客车从甲城开往乙城，每小时行36千米，2小时后，一辆面包车从乙城开往甲城，每小时行54千米．大客车在行过甲、乙两城中点9千米处与面包车相遇．甲城和乙城相距多少千米．
<gadget id="calculator">2 / 36</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">36 * (1/18)</gadget>
<output>2</output>

<gadget id="calculator">9 / 36</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">9 / 54</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">2 - (1/4) - (1/6)</gadget>
<output>19/12 = around 1.583333</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 36</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">(1/2) * (1/36)</gadget>
<output>1/72 = around 0.013889</output>

<gadget id="calculator">1 / 54</gadget>
<output>1/54 = around 0.018519</output>

<gadget id="calculator">(1/2) * (1/54)</gadget>
<output>1/108 = around 0.009259</output>

<gadget id="calculator">(1/72) - (1/108)</gadget>
<output>1/216 = around 0.00463</output>

<gadget id="calculator">(19/12) / (1/216)</gadget>
<output>342</output>

<result>342</result>