A factory produces a product, and the cost of each product is reduced from 40 yuan to 36.4 yuan. What percentage is the reduction?
某厂生产一种产品，每件产品的成本由40元降低到36.4元，降低了百分之几？
<gadget id="calculator">40 - 36.4</gadget>
<output>3.6</output>

<gadget id="calculator">3.6 / 40</gadget>
<output>0.09</output>

<result>0.09</result>