24 students in the fourth grade were divided into 3 groups on average to collect used batteries in the community, and each person collected an average of 25 batteries. It is known that the first group collected an average of 20 knots per person, and the second group collected a total of 200 knots. Calculate how many knots each person in the third group collects on average.
四年级24位同学平均分成3个小组到小区收集废旧电池，结果平均每人收集了25节．已知第一小组平均每人收集20节，第二小组共收集200节．算算，第三小组平均每人收集多少节．
<gadget id="calculator">24 * 25</gadget>
<output>600</output>

<gadget id="calculator">24 / 3</gadget>
<output>8</output>

<gadget id="calculator">8 * 20</gadget>
<output>160</output>

<gadget id="calculator">600 - 160 - 200</gadget>
<output>240</output>

<gadget id="calculator">240 / 8</gadget>
<output>30</output>

<result>30</result>