Every adult passenger on the plane can carry 20 kilograms of luggage free of charge. If it exceeds 20 kilograms, the luggage fee of 1.5% of the original price of the air ticket will be paid for each kilogram of the excess part. Uncle Wang flew from Beijing to Nanjing, and the air fare was 540 yuan after a 40% discount. Uncle Wang brought 30 kilograms of luggage, how much is the luggage fee?
乘坐飞机的每位成人旅客，可以免费携带20千克行李，如果超过20千克，超过的部分每千克需按飞机票原价的1.5%付行李费．王叔叔从北京乘飞机到南京，飞机票价打六折后是540元．王叔叔带了30千克的行李，应付行李费多少元？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">540 / (3/5)</gadget>
<output>900</output>

<gadget id="calculator">30 - 20</gadget>
<output>10</output>

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

<gadget id="calculator">900 * 10 * 0.015</gadget>
<output>135</output>

<result>135</result>