The whole class goes rowing. If there is one less boat, there will be exactly 9 students in each boat; if there is one more boat, there will be exactly 6 students in each boat. How many students are there in this class.
全班同学去划船，如果减少一条船，每条船正好坐9个同学；如果增加一条船，每条船正好坐6个同学．这个班有多少个同学．
<gadget id="calculator">9 + 6</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">6 * 5</gadget>
<output>30</output>

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

<result>36</result>