Buying 1 kg of apples and 1 kg of pears costs 20.8 yuan, and buying 4 kg of apples and 7 kg of pears costs 112 yuan. How much is an apple per kilogram?
买1千克苹果和1千克梨共20.8元，买4千克苹果和7千克梨共112元．每千克苹果多少元？
<gadget id="calculator">20.8 * 7</gadget>
<output>145.6</output>

<gadget id="calculator">145.6 - 112</gadget>
<output>33.6</output>

<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<gadget id="calculator">33.6 / 3</gadget>
<output>11.2</output>

<result>11.2</result>