Mom bought 2 kilograms of apples and 2 kilograms of oranges. The total cost was 16.2 yuan. The oranges were 2.8 yuan per kilogram. How much is the apple per kilogram? (solution by equation)
妈妈买了2千克苹果和2千克橘子，一共花了16.2元，橘子每千克2.8元，苹果每千克多少元？(用方程解)
<gadget id="calculator">2.8 * 2</gadget>
<output>5.6</output>

<gadget id="calculator">16.2 - 5.6</gadget>
<output>10.6</output>

<gadget id="calculator">10.6 / 2</gadget>
<output>5.3</output>

<result>5.3</result>