The ratio of the number of boys to the number of girls in the second class of the fifth grade is 3:2. It is known that there are 42 boys. How many girls are there in this class?
五年级二班男生人数与女生人数之比是3：2，已知男生人数有42人，这个班女生人数是多少人？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">42 * (2/3)</gadget>
<output>28</output>

<result>28</result>