The fourth-grade students go rowing on the "May and First" festival. If one more boat is added, each boat can accommodate exactly 6 people; if one boat is reduced, each boat can accommodate exactly 9 people. How many people are there in total?
四年级同学"五、一"节去划船，如果增加一条船，每条船正好坐6人；如果减少一条船，每条船正好坐9人，共有多少人坐船？
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

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

<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">4 * 9</gadget>
<output>36</output>

<result>36</result>