Naughty bought apples and pears for a total of 85 yuan. The unit prices of apples and pears are 4 yuan and 5 yuan per kilogram respectively. He bought 5 kilograms of apples. How many kilograms of pears did he buy? (solution with equation)
淘气买苹果和梨一共用了85元，苹果和梨的单价分别是每千克4元和5元，他买了5千克苹果，他买梨多少千克？(用方程解答)
<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">85 - 20</gadget>
<output>65</output>

<gadget id="calculator">65 / 5</gadget>
<output>13</output>

<result>13</result>