The number of students from a certain school who signed up for the "Hope Cup" National Mathematics Invitational Competition was 1/5 of the number of unregistered students. Later, another 180 students signed up. At this time, the number of registered students was 1/3 of the number of unregistered students. How many students are there in this school?
某校学生报名参加"希望杯"全国数学邀请赛的人数是未报名的人数的(1/5)，后来又有180名同学报名，此时报名的人数是未报名人数的(1/3)，这个学校有学生多少人．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + 5</gadget>
<output>6</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/4) - (1/6)</gadget>
<output>1/12 = around 0.083333</output>

<gadget id="calculator">180 / (1/12)</gadget>
<output>2_160</output>

<result>2_160</result>