Two groups of students participate in "science and technology" activities. The number of students in group A is three times that of group B, and the number of students in group B is 40 less than that of group A. How many students participate in "science and technology" activities?
两组学生参加"科技"活动，甲组人数是乙组的3倍，而乙组人数比甲组少40人，参加"科技"活动的学生有多少．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<gadget id="calculator">20 + 60</gadget>
<output>80</output>

<result>80</result>