With 27.2 yuan, Xiaohong can just buy 5 kilograms of apples and 4 kilograms of oranges, but she reverses the quantity she bought, leaving 0.4 yuan. How much is an orange per kilogram?
小红用27.2元正好可以买5千克苹果和4千克橘子，结果她把买的数量颠倒了，剩下0.4元．橘子每千克多少元？
<gadget id="calculator">27.2 - 0.4</gadget>
<output>26.8</output>

<gadget id="calculator">26.8 * 5</gadget>
<output>134</output>

<gadget id="calculator">27.2 * 4</gadget>
<output>108.8</output>

<gadget id="calculator">134 - 108.8</gadget>
<output>25.2</output>

<gadget id="calculator">25 - 16</gadget>
<output>9</output>

<gadget id="calculator">25.2 / 9</gadget>
<output>2.8</output>

<result>2.8</result>