Two cars, A and B, drive from opposite places at the same time. After 9 hours, the two cars meet. How many hours does it take for car B to complete the journey?
甲乙两车同时从两地相对开出，9小时后两车相遇，相遇时甲车正好行全程的(2/5)．乙车行完全程需要多少小时？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(3/5) / 9</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / (1/15)</gadget>
<output>15</output>

<result>15</result>