18. [-/5 Points] DETAILS MY NOTES A company is decreasing production of math-brain protein bars at a rate of 100 cases per day. All cases produced can be sold. The daily demand function is given by P(x) = 80 - X 200 where x is the number of cases produced and sold, and p is in dollars. Find the rate of change of the revenue with respect to the time In days when the daily production is 800 cases. O -7,700 dollars per day O -8,000 dollars per day -7,200 dollars per day O -7,800 dollars per day O -7,100 dollars per day