There are 9 girls visiting the observatory, and the number of boys visiting is 1 person more than 3 times that of girls. How many boys are there?
去天文台参观的女生有9人，男生去的人数比女生的3倍还多1人．男生有多少人？
<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<gadget id="calculator">27 + 1</gadget>
<output>28</output>

<result>28</result>