Apples cost 6 yuan per kilogram, and citrus fruits cost 4 yuan per kilogram. Xiaohua takes 50 yuan and buys 5 kilograms of citrus. How many kilograms of apples can he buy with the remaining money?
苹果每千克6元，柑橘每千克4元，小华带50元钱，买5千克柑橘，剩下的钱能买几千克苹果？
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">50 - 20</gadget>
<output>30</output>

<gadget id="calculator">30 / 6</gadget>
<output>5</output>

<result>5</result>