The number of boys in Class 3 is twice the number of girls. There are 40 boys in class 31, how many are there in total?
三1班男生人数是女生人数的2倍．三1班男生有40人，一共有多少人？
<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 + 40</gadget>
<output>60</output>

<result>60</result>