An express train and a local train depart from A at the same time and travel between A and B. The express train travels to place B for 10 hours. At this time, the slow train reaches the midpoint between places A and B. The express train stops at place B for 1 hour and returns from place B. Ask: How many hours can the express train travel from place B to Slow train meet?
一列快车和一列慢车同时从甲地出发，往返于甲、乙两地之间．快车行驶10小时到乙地，这时慢车才行至甲、乙两地的中点，快车在乙地停车1小时后，又从乙地返回，问：快车从乙地驶出几小时可与慢车相遇？
<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(1/20) * 11</gadget>
<output>11/20 = around 0.55</output>

<gadget id="calculator">1 - (11/20)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) + (1/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(9/20) / (3/20)</gadget>
<output>3</output>

<result>3</result>