One job, A works alone for 10 hours, B's work efficiency is (5/6) times that of A, and C's work efficiency is (5/4), A and B work together for 2 hours first, then C joins in and does How many hours will it take to finish this job?
一件工作，甲独做10小时，乙的工作效率是甲的(5/6)倍，丙的工作效率是甲的(5/4)，甲乙先合干2个小时后，丙加入，做完这件工作还要几小时？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">5 / 6</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">(1/10) * (5/6)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/10) + (1/12)</gadget>
<output>11/60 = around 0.183333</output>

<gadget id="calculator">(11/60) * 2</gadget>
<output>11/30 = around 0.366667</output>

<gadget id="calculator">1 - (11/30)</gadget>
<output>19/30 = around 0.633333</output>

<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">(1/10) * (5/4)</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">(1/10) + (1/12) + (1/8)</gadget>
<output>37/120 = around 0.308333</output>

<gadget id="calculator">(19/30) / (37/120)</gadget>
<output>76/37 = around 2.054054</output>

<result>76/37 = around 2.054054</result>