The students hold a parade performance, with 20 people in each row, which can be arranged in 9 rows. If they are arranged in 6 rows, how many people are there in each row?
同学们举行队列表演，每列20人，可以排成9列，如果排成6列，每列有多少人？
<gadget id="calculator">9 / 6</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">20 * (3/2)</gadget>
<output>30</output>

<result>30</result>