The speed ratio of the two vehicles A and B is 2:9. The two vehicles start from A and B at the same time and meet each other for 5 hours. If the two vehicles start from A and B at the same time and travel in the same direction, A If B is in the front, how many hours does it take for B to catch up with A?
甲、乙两车的速度比是2：9，两车分别从A、B两地同时出发，相向而行5小时相遇，如果两车从A、B两地同时出发，同向而行，甲在前乙在后，那么乙需要多少小时追上甲．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 + 9</gadget>
<output>11</output>

<gadget id="calculator">9 / 11</gadget>
<output>9/11 = around 0.818182</output>

<gadget id="calculator">(1/5) * (9/11)</gadget>
<output>9/55 = around 0.163636</output>

<gadget id="calculator">2 / 11</gadget>
<output>2/11 = around 0.181818</output>

<gadget id="calculator">(1/5) * (2/11)</gadget>
<output>2/55 = around 0.036364</output>

<gadget id="calculator">(9/55) - (2/55)</gadget>
<output>7/55 = around 0.127273</output>

<gadget id="calculator">1 / (7/55)</gadget>
<output>55/7 = around 7.857143</output>

<result>55/7 = around 7.857143</result>