Question 976498
Maximizing revenue:

100x-x^2/8= maximum.  This will be a negative quadratic, and the vertex is maximum.


vertex is -b/2a = -100/-1/4=400
That is the x-value of pillows.

400 pillows--revenue is (40,000-20,000)=20,000
399 pillows--revenue is (39900-19,900.125)=19999.875
401 pillows--revenue is (40100-20100.25)=19999.75

{{{graph(300,200,-100,1000,-1000,20000,(-x^2/8)+100x)}}}