The large warehouse has 50 tons of flour, and the small warehouse has 20 tons of flour. If the same amount of flour is taken from the two warehouses, the remaining amount in the large warehouse is three times that of the small warehouse. How many tons of flour were shipped from the two warehouses?
大仓库有面粉50吨，小仓库有面粉20吨，从两个仓库运走同样多的面粉，大仓库剩下的是小仓库剩下的3倍．从两个仓库共运走多少吨面粉．
<gadget id="calculator">3 * 20</gadget>
<output>60</output>

<gadget id="calculator">60 - 50</gadget>
<output>10</output>

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

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<result>10</result>