Planting trees will benefit future generations. The students planted a total of 2,150 trees in the first 4 hours, and an average of 520 trees per hour in the next 3 hours. How many trees do the students plant per hour on average?
植树造林，造福千秋，同学们前4小时共植树2150棵，后3小时平均每小时植树520棵．同学们平均每小时植树多少棵？
<gadget id="calculator">520 * 3</gadget>
<output>1_560</output>

<gadget id="calculator">1_560 + 2_150</gadget>
<output>3_710</output>

<gadget id="calculator">4 + 3</gadget>
<output>7</output>

<gadget id="calculator">3_710 / 7</gadget>
<output>530</output>

<result>530</result>