The students in the manual group made a total of 210 small red flags, 150 small yellow flags and 90 small green flags. If there are 30 small flags for each class, how many classes can these colorful flags be divided into?
手工小组的同学一共制作了210面小红旗.150面小黄旗和90面小绿旗，如果每班分30面，这些彩旗一共可以分给几个班？
<gadget id="calculator">210 + 150 + 90</gadget>
<output>450</output>

<gadget id="calculator">450 / 30</gadget>
<output>15</output>

<result>15</result>