For a manuscript, it takes 6 hours for A and B to finish it together, and 10 hours for A to finish it alone. How many hours does it take for B to finish it alone?
一份文稿，甲、乙合打要6小时完成，甲独打要10小时完成，乙单独打多少小时完成？
<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/6) - (1/10)</gadget>
<output>1/15 = around 0.066667</output>

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

<result>15</result>