The number of people in the science and technology interest group is between 40-50, and the ratio of the number of boys to the number of girls is 5:4. How many boys are there in this interest group?
科技兴趣小组人数在40-50人之间，男生人数与女生人数的比是5：4，这个兴趣小组的男生有多少人？
<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<gadget id="calculator">45 * (5/9)</gadget>
<output>25</output>

<result>25</result>