There are 30 students reading in the reading room of the school. The ratio of boys and girls is 2:3. Later, some girls came to read. At this time, the number of girls accounted for 2/3 of the total number of students. How many girls came to read later?
学校阅览室有30名学生在看书，男生女生人数比是2：3，后来又有一些女生来看书，这时女生人数占所有人数的(2/3)，问后来有多少名女生来看书？
<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">30 * (2/5)</gadget>
<output>12</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">12 / (1/3)</gadget>
<output>36</output>

<gadget id="calculator">36 - 30</gadget>
<output>6</output>

<result>6</result>