
Yefim S. answered 11/30/21
Math Tutor with Experience
Let we have x reduction in price. Then new price is (8 - 0.5x) and sale is (100 + 20x).
So, revenue R(x) = (8 - 0.5x)(100 + 20x) = 800 + 110x - 10x2; R'(x) = 110 - 20x = 0; x = 5.5
But we can't reduce price 5.5 timec we have take x = 5 or 6.
Let calculate revenu: R(5) = (8 - 2.5)(100 + 100) = 1100
R(6) = (8 - 3)(100 + 120) = 1100.
Price: 8 - 2.5 = $5.5 and price 8 - 3 = $5 give the same max revenue $1100