It takes 4 hours for a batch of materials to be transported by car A alone, and 6 hours for car B to transport it alone. How many hours will it take for (5/6) the two vehicles A and B to jointly transport this batch of materials?
一批物资，甲车单独运完需4小时，乙车单独运完需6小时．现在由甲、乙两车合运这批物资的(5/6)，需要多少小时？
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/4) + (1/6)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">(5/6) / (5/12)</gadget>
<output>2</output>

<result>2</result>