Since the number of products sold is x=250, the coresponding price is
P=2000−0.2(250)−0.01(250)2=1325 The consumer surplus is as follows
∫0250(p(x)−P)dx 
=∫0250(2000−0.2x−0.01x2−1325)dx 
=[675x−0.1x2−30.01x3]2500 
=675(250)−0.1(250)2−30.01(250)3 
=$110416.67 
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