Two workers, A and B, produce the same part, 15% of the number of parts produced by worker A in 2 hours is equivalent to the number of parts produced by worker B in 0.5 hours. How much slower is worker B's work efficiency than worker A's work efficiency
甲乙两名工人生产同一种零件，甲工人2小时所生产零件数量的15%，相当于乙工人0.5小时所生产零件的数量．乙工人的工作效率比甲工人的工作效率慢多少
<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(3/20) / 0.5</gadget>
<output>0.3</output>

<gadget id="calculator">2 * 0.3</gadget>
<output>0.6</output>

<gadget id="calculator">1 - 0.6</gadget>
<output>0.4</output>

<gadget id="calculator">0.4 / 1</gadget>
<output>0.4</output>

<result>0.4</result>