For a batch of parts, 15% and 10 of them are produced every day, and it can be completed in 5 days. How many parts are there in this batch?
一批零件，每天生产它的15%又10个，5天就可以完成．这批零件有多少个？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(1/5) - (3/20)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">10 / (1/20)</gadget>
<output>200</output>

<result>200</result>