There are 90 students, and there are two desks for each two. If these desks are placed in 3 classrooms on average, how many desks are placed in each classroom?
有90名学生，每两人用一张桌子，如果把这些桌子平均放在3间教室里，那么每间教室放多少张？
<gadget id="calculator">90 / 2 / 3</gadget>
<output>15</output>

<result>15</result>