Xiaohong's mother went to the grain store and bought 20 kilograms of rice and 15 kilograms of flour for 100 yuan. It is known that rice is 3.2 yuan per kilogram, how much is flour per kilogram? (solution by equation)
小红妈妈到粮店买了20千克大米和15千克面粉，共用去100元．已知大米每千克3.2元，面粉每千克多少元？(用方程解)
<gadget id="calculator">3.2 * 20</gadget>
<output>64</output>

<gadget id="calculator">100 - 64</gadget>
<output>36</output>

<gadget id="calculator">36 / 15</gadget>
<output>12/5 = around 2.4</output>

<result>12/5 = around 2.4</result>