Profit P = r-C=-298*p^2+18360*p-(-6854*p+434280) =-298*p^2

Put the profit function in standard form. Determine the coefficients a, b, and c. Use those coefficients to determine the vertex of the parabola. This will give you a theoretical derivation of the best price to charge, and of what the maximum profit will be. Use this information to determine how many backpacks to make per month.