Students participating in the "June 1st" gymnastics performance, the number of people in each horizontal row is the same, and the number of people in each vertical row is also the same. Wang Jing's position is the 10th person from the left, the 6th person from the right, the 12th person from the front, and the 9th person from the back. How many students participated in the performance?
同学参加"六一"体操表演，每横排人数同样多，每竖排人数也同样多．王菁的位置是从左数第10人，从右数第6人，从前数第12人，从后数是第9人．参加表演的同学有多少人．
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">10 + 5</gadget>
<output>15</output>

<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">12 + 8</gadget>
<output>20</output>

<gadget id="calculator">15 * 20</gadget>
<output>300</output>

<result>300</result>