A project can be completed by A alone in 8 hours, B alone in 12 hours, and C alone in 15 hours. After A and B cooperate for 2 hours, B and C cooperate for another 3 hours, and C alone completes the rest. How many hours to complete?
一项工程，甲单独做8小时完成，乙单独做12小时，丙单独做15小时完成，甲、乙合作2小时后，乙、丙再合作3小时，剩下的由丙单独完成，还需几小时完成？
<gadget id="calculator">1 / 8</gadget>
<output>1/8 = around 0.125</output>

<gadget id="calculator">1 / 12</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">(1/8) + (1/12)</gadget>
<output>5/24 = around 0.208333</output>

<gadget id="calculator">(5/24) * 2</gadget>
<output>5/12 = around 0.416667</output>

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

<gadget id="calculator">(1/12) + (1/15)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(3/20) * 3</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (5/12) - (9/20)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">(2/15) / (1/15)</gadget>
<output>2</output>

<result>2</result>