A person inherits money and wants to invest in a stock fund and a bond fund. The returns are 6% for the bond and 10% for the stock. He wants to invest a portion of the inheritance with at least 30% going to the bond. He wants to select a mix that will enable his to obtain a total return of 7.5%. What is the linear programming model that can be used to determine the % that should be allocated to each of the possible investment alternatives? Solve the problem using the graphical solution procedure.