Class 4 of the sixth grade went rowing in Jingxiu Park. They planned that if one more boat was added, each boat would have exactly 6 people; if one boat was reduced, each boat would have exactly 9 people.
六年级4班去竞秀公园划船，他们计划了一下，如果增加一条船，正好每条船上坐6人；如果减少一条船，正好每条船上坐9人，六年级4班有多少人？
<gadget id="calculator">6 + 9</gadget>
<output>15</output>

<gadget id="calculator">9 - 6</gadget>
<output>3</output>

<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<gadget id="calculator">30 + 6</gadget>
<output>36</output>

<result>36</result>