A and B set off from AB at the same time and walk towards each other, and they can meet each other after 12 hours. Now car A starts first, and car B starts 2 hours later. One hour after car B departs, the two cars have traveled 15% of the whole journey. How many hours does it take for car A to complete the journey?
甲乙两人分别从AB两地同时出发相向而行，12个小时后可以相遇．现在甲车先出发，2小时后乙车才出发，乙车出发后1小时，两车共行了全程的15%．甲车行完全程要几小时？
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/12) * 1</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(3/20) - (1/12)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/15) / 2</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / (1/30)</gadget>
<output>30</output>

<result>30</result>