A task can be completed by A alone in 5 days and B alone in 4 days. A's work efficiency is equal to B's work efficiency.
一项任务，甲单独做5天完成，乙单独做4天完成，甲的工作效率是乙工作效率的多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<result>4/5 = around 0.8</result>