Among the students in Class 4 of the sixth grade, (2/3) of the students like to dance, (3/4) of the students like to sing, and there is no one who does not like to dance and sing. It is known that there are 20 people who like both dancing and singing. How many students are there in Class 4, Grade 6?
六年级四班学生中有(2/3)的同学喜欢跳舞，(3/4)的同学喜欢唱歌，没有人既不喜欢跳舞又不喜欢唱歌．已知既喜欢跳舞又喜欢唱歌的有20人，六年级四班共有学生多少人？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

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

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

<gadget id="calculator">(2/3) + (-1/4)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">20 / (5/12)</gadget>
<output>48</output>

<result>48</result>