The fruit shop brings in a batch of oranges, and sells (2/7) of the total in 3 days, leaving 150 kilograms. How many kilograms of oranges are sold per day on average?
水果店运进一批桔子，3天共售出总数的(2/7)，还剩150千克，平均每天售出桔子多少千克？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">150 / (5/7)</gadget>
<output>210</output>

<gadget id="calculator">(2/7) / 3</gadget>
<output>2/21 = around 0.095238</output>

<gadget id="calculator">210 * (2/21)</gadget>
<output>20</output>

<result>20</result>