Every passenger who takes an airplane and carries more than 20 kilograms of luggage must purchase a luggage ticket at 1.5% of the original price of the plane ticket for each kilogram. Mr. Liu is traveling from Xi'an to Nanjing. The air fare is 864 yuan after a 20% discount. He has 60 kilograms of luggage. How much is the luggage fee?
乘坐飞机的每位旅客，携带行李超过20千克的部分，每千克要按飞机票原价的1.5%购买行李票．刘先生从西安到南京，飞机票价八折后是864元，他带了60千克行李，应付行李费多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">864 / (4/5)</gadget>
<output>1_080</output>

<gadget id="calculator">60 - 20</gadget>
<output>40</output>

<gadget id="calculator">1.5 / 100</gadget>
<output>0.015</output>

<gadget id="calculator">1_080 * 40 * 0.015</gadget>
<output>648</output>

<result>648</result>