Master Wang used to take 50 minutes to make a Haibao toy, but now he can finish it in 20 minutes. How much has his work efficiency improved?
王师傅原来做一个海宝玩具要50分钟，现在20分钟就可以完成，他的工作效率提高了多少
<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 / 50</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/20) - (1/50)</gadget>
<output>3/100 = around 0.03</output>

<gadget id="calculator">(3/100) / (1/50)</gadget>
<output>3/2 = around 1.5</output>

<result>3/2 = around 1.5</result>