Master Zhang wants to process a batch of parts, and plans to process 200 parts per day, which will be completed in 15 days. If it is required to be completed in 10 days, how much should the work efficiency be improved?
张师傅要加工一批零件，计划每天加工200个，15天完成．如果要求10天完成，工作效率应提高多少．
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 / 15</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">(1/10) - (1/15)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">(1/30) / (1/15)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>