Qingfeng Primary School held a calligraphy and painting competition to celebrate "June 1st". The number of girls participating in the competition was 30 more than that of boys. The result of the competition is: all the boys will win, 60% of the girls will win, and the number of girls and boys will be equal. How many boys are there in the competition?
庆丰小学举办了庆"六一"书画比赛，参加比赛的女生比男生多30人．比赛的结果是：男生全部获奖，女生有60%获奖，女生和男生获奖的人数相等．参加比赛的男生有多少人？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">30 / (2/5)</gadget>
<output>75</output>

<gadget id="calculator">75 - 30</gadget>
<output>45</output>

<result>45</result>