A class of students held a calligraphy competition, in which the number of girls participating in the competition was (1/2) the number of boys. If 2 boys were replaced by girls, then the number of girls was (2/3) the number of boys. This calligraphy competition How many people participated in total.
某班学生举行一场书法比赛，其中参赛的女生人数是男生人数的(1/2)，如果把2名男生换成女生，那么女生人数是男生人数的(2/3)，这场书法比赛共有多少人参赛．
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(2/5) - (1/3)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">2 / (1/15)</gadget>
<output>30</output>

<result>30</result>