A cylindrical bucket is filled with three-fifths of the bucket of water, and after pouring out one-third of the water in the bucket, there is still 40 liters of water left. Given that the height of the bucket is 8 decimeters, what is the area of the bottom of the bucket in square decimeters?
一个圆柱形水桶，里面装了五分之三桶水，倒出桶中水的三分之一后，还剩下40升水．已知水桶的高是8分米，这个水桶的底面积是多少平方分米．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(3/5) * (2/3)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 / (2/5) / 8</gadget>
<output>25/2 = around 12.5</output>

<result>25/2 = around 12.5</result>