Aunt Wang used 50 yuan to buy 16.5 kilograms of rice, and she had to pay 2.40 yuan per kilogram of rice. How much should the salesperson give Aunt Wang?
王大妈用50元钱去买16.5千克大米，每千克大米要付2.40元钱，营业员应找给王大妈多少元钱？
<gadget id="calculator">2.4 * 16.5</gadget>
<output>39.6</output>

<gadget id="calculator">50 - 39.6</gadget>
<output>10.4</output>

<result>10.4</result>