There is a pile of goods, it takes 15 times to transport them by car A alone, and 10 times by car B alone. If two cars are used to transport them at the same time, how many times can they be transported?
有一堆货物，用甲车单独运需要15次，用乙车单独运需要10次，如果用两车同时运，几次就可以运完？
<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

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

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

<result>6</result>