If 10 out of 400 parts are unqualified, what is the pass rate of this batch of parts?
400个零件中有10个不合格，这批零件的合格率为多少．
<gadget id="calculator">400 - 10</gadget>
<output>390</output>

<gadget id="calculator">390 / 400</gadget>
<output>39/40 = around 0.975</output>

<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">(39/40) * 1</gadget>
<output>39/40 = around 0.975</output>

<result>39/40 = around 0.975</result>