In a survey, in Class 5 and 3, those who liked mathematics accounted for (4/5) of the whole class, those who liked Chinese accounted for (3/4) of the whole class, and those who didn't like both subjects accounted for (1/5) of the whole class. 20). What percentage of the class are people who like both subjects?
在一次调查中，五3班喜欢数学的占全班人数的(4/5)，喜欢语文的占全班人数的(3/4)，两科都不喜欢的占全班人数的(1/20)．两科都喜欢的人数占全班人数的几分之几？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 - (1/20)</gadget>
<output>19/20 = around 0.95</output>

<gadget id="calculator">(3/4) - (19/20)</gadget>
<output>-1/5 = around -0.2</output>

<gadget id="calculator">(4/5) + (-1/5)</gadget>
<output>3/5 = around 0.6</output>

<result>3/5 = around 0.6</result>