SALES: A soft-drink vendor at a popular beach analyzes his sales records, and finds that if he sales x cans of soda pop in one day , his profit (in dollars) is given by P(x)= -0.001x^2+3x-1800
#69 The profit that the vendor makes per day by selling x pretzels is given by the function P(x)=4x˄2+2400x-200.Find the number of pretzels that must be sold to maximize profit.