The Public Welfare Micro Lecture Hall organized a mock exam for junior high school in the sixth grade. A total of 2,800 students participated, of which boys accounted for 3/7 of the total. When the exam was approaching, some boys signed up. At this time, boys accounted for the total number (7/15), so how many boys signed up when the exam was approaching?
公益微讲堂六年级组织了一次小升初模考，共有2800名学生参加，其中男生占总数的(3/7)，临近考试时，又有一些男生报名参加．这时男生占总人数的(7/15)，那么临近考试时，有多少个男生报名参加？
<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">2_800 * (3/7)</gadget>
<output>1_200</output>

<gadget id="calculator">2_800 - 1_200</gadget>
<output>1_600</output>

<gadget id="calculator">7 / 15</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">1 - (7/15)</gadget>
<output>8/15 = around 0.533333</output>

<gadget id="calculator">1_600 / (8/15)</gadget>
<output>3_000</output>

<gadget id="calculator">3_000 - 2_800</gadget>
<output>200</output>

<result>200</result>