There is a batch of goods shipped twice, and the first shipment is 6 tons more than three times the second shipment. If the first shipment reduced by 78 tons and the second shipment increased by 78 tons, the two shipments are equal in quantity. How many tons are there in total for this batch of goods?
有一批货物分两次运，第一次运来的货物比第二次运来的3倍多6吨．如果第一次运来的货物减少78吨，而且第二次运来的货物增加78吨，则两次运来的货物数量相等．这批货物共有多少吨．
<gadget id="calculator">78 - 6</gadget>
<output>72</output>

<gadget id="calculator">78 + 72</gadget>
<output>150</output>

<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">150 / 2</gadget>
<output>75</output>

<gadget id="calculator">4 * 75</gadget>
<output>300</output>

<gadget id="calculator">300 + 6</gadget>
<output>306</output>

<result>306</result>