Answer:
Maximum price = GH¢85
Explanation:
Let p be the number of times she raises the price as well as the number of times 10 less plates are sold
Revenue, R = number of plates sold * price sold
R = (300 - 10p)(20 + 5p)
R = 6000 + 1500p - 200p - 50p²
R = 6000 + 1300p - 50p²
50p² - 1300p - 6000 = 0
p² - 26p - 120 = 0
finding the axis of symmetry, p = -b/2a
p = -(-26)/2*1
p = 13
Maximum price = 13 * 5 + 20 = GH¢85
Number of plates sold = 300 - 10 * 13 = 170 plates
Maximum revenue = GH¢85 * 170 = GH¢14,450