project can be completed by team A alone in 10 days and by team B in 15 days alone. If teams A and B cooperate, how many days will it take to complete the project (5/6).
一项工程，甲队单独做10天完成，乙队单独做15天完成．若甲、乙两队合作，多少天可完成这项工程的(5/6)．
<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<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">(5/6) / (1/6)</gadget>
<output>5</output>

<result>5</result>