The task of processing a batch of parts was originally planned to be allocated to A and B according to the 5:3 ratio. If they start working at the same time, they can complete the task at the same time. In fact, for some reason, when two people start work at the same time, A's work efficiency will be reduced by 40% compared with the original plan, and B's work efficiency will remain unchanged. In this way, when B completes his task, he immediately helps A to process together, and completes the entire task after another 2 hours. If all parts of this batch are processed by B alone, how many hours will it take to complete.
把加工一批零件的任务，原计划按5：3分配给甲、乙两人，如果他们同时开工就可以同时完成任务．实际用于某种原因，二人同时一开工，甲的工作效率就比原计划降低了40%，乙的工作效率不变．这样，当乙完成了自己的任务后，立即帮助甲一起加工，又经过2小时完成了全部任务，如果这批零件全部由乙单独加工，需要多少小时完成．
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(5/8) - (3/8)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(1/4) / 2 / 2</gadget>
<output>1/16 = around 0.0625</output>

<gadget id="calculator">1 / (1/16)</gadget>
<output>16</output>

<result>16</result>