There are 6 people sitting at one table, 10 people sitting at two tables, and 14 people sitting at three tables... In this way, how many people can sit at 7 tables in a row?
一张桌子坐6人，两张桌子坐10人，三张桌子坐14人…照这样，7张桌子并成一排坐多少人．
<gadget id="calculator">4 * 7</gadget>
<output>28</output>

<gadget id="calculator">28 + 2</gadget>
<output>30</output>

<result>30</result>