There are 49 students in Class 5 and 2 of a certain school. The ratio of male to female students is 3:4. How many boys are there in this class?
某校五2班共有学生49人，男女生人数的比是3：4，这个班的男生有多少人？
<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">49 / 7</gadget>
<output>7</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<result>21</result>