There are three schools, A, B, and C. The number of students in school A is (1/2) the sum of the two schools, B and C. The students in school B account for (2/5) the number of students in the three schools. School B has 100 more students than School A. How many students are there in the three schools?
甲乙丙三件学校，甲校人数是乙丙两校和的(1/2)，乙校学生占三间学校人数的(2/5)．乙校学生人数比甲校多100人，三间学校共有多少人？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + 2</gadget>
<output>3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(2/5) - (1/3)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">100 / (1/15)</gadget>
<output>1_500</output>

<result>1_500</result>