There are 45 students in Class 5 and 2, including 21 boys. What percentage of the whole class are boys?
五2班有学生45人，其中男生21人，男生占全班人数的几分之几？
<gadget id="calculator">21 / 45</gadget>
<output>7/15 = around 0.466667</output>

<result>7/15 = around 0.466667</result>