Mom bought 4 kilograms of apples, handed them to the salesperson for 30 yuan, and got back 4.8 yuan. How much is each kilogram of apples?
妈妈买了4千克苹果，交给售货员30元，找回4.8元，每千克苹果多少元？
<gadget id="calculator">30 - 4.8</gadget>
<output>25.2</output>

<gadget id="calculator">25.2 / 4</gadget>
<output>6.3</output>

<result>6.3</result>