There are two cars A and B. Car A drives from city A to city B and arrives in 10 hours. B drives from city B to city A and arrives in 15 hours. Cars A and B leave the two cities opposite each other at the same time. When will they meet?
甲、乙两辆汽车，甲车从A城开往B城，10h到达，乙从B城开往A城，15h到达，甲、乙两车同时从两城相对开出，几小时相遇？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) + (1/15)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<result>6</result>