batch of parts can be completed by A in 10 hours alone. After 2 hours of A’s work, B comes to participate. The two work together for 3 hours to complete the task. How many hours does B need to work alone?
一批零件，甲单独做10小时完成，甲做2小时后，乙来参加，两人台作3小时完成任务，乙单独做共要几小时？
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 2</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(4/5) / 3</gadget>
<output>4/15 = around 0.266667</output>

<gadget id="calculator">(4/15) - (1/10)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 / (1/6)</gadget>
<output>6</output>

<result>6</result>