To do a project alone, A needs 10 hours, and B needs 15 hours. If A and B cooperate, how many hours can complete half of the whole project?
单独做一项工程，甲需要10h，乙需要15h，如果甲乙合作，多少小时能完成全工程的一半？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</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">(1/2) / (1/6)</gadget>
<output>3</output>

<result>3</result>