In a class of students, 65% like swimming, 75% like painting, 85% like singing, and 95% like playing chess. What is the minimum percentage of students in this class who have these four hobbies at the same time?
某班学生中，65%的喜欢游泳，75%喜欢绘画，85%喜欢唱歌，95%喜欢下棋，该班学生同时有这四种爱好的学生所占的最小百分比是多少．
<gadget id="calculator">100 / 100</gadget>
<output>1</output>

<gadget id="calculator">65 / 100</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">1 - (13/20)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">75 / 100</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 - (3/4)</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">1 - (17/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">95 / 100</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">1 - (19/20)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">(7/20) + (1/4) + (3/20) + (1/20)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>