It takes 7 hours for a local train to travel from station A to station B, and 6 hours for an express train to travel from station B to station A. The two trains are traveling towards each other. One hour after the slow train leaves station A, the express train departs from station B. How many hours will it take to meet the slow train?
一列慢车从甲站到乙站要7小时，一列快车从乙站到甲站要6小时，两车相向而行，慢车从甲站开出1小时后，快车才从乙站开出，快车开出几小时后才能和慢车相遇？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/7) * 1</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (1/7)</gadget>
<output>6/7 = around 0.857143</output>

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

<gadget id="calculator">(1/7) + (1/6)</gadget>
<output>13/42 = around 0.309524</output>

<gadget id="calculator">(6/7) / (13/42)</gadget>
<output>36/13 = around 2.769231</output>

<result>36/13 = around 2.769231</result>