Thirty liters of a 40% acid solution is obtained by mixing a 25% solution with a 50% solution.
(a) Write a system of equations in which one equation represents the total amount of final mixture required and the other represents the percent of acid in the final mixture. Let x and y represent the amounts of the 25% and 50% solutions, respectively.
(b) Use a graphing utility to graph the two equations in part (a) in the same viewing window. As the amount of the 25% solution increases, how does the amount of the 50% solution change?
(c) How much of each solution is required to obtain the specified concentration of the final mixture?