An investment firm has $600,000 on the account. The chief investment officer would like to reinvest the $600,000 in a portfolio that would maximize return on investment while at the same time maintaining a relatively conservative mix of stocks and bonds. The following table shows the investment opportunities and rates of return.

Investment Opportunity	Rate of Return
Municipal Bonds	0.065
High Tech Stock	0.120
Blue Chip Stock	0.095
Federal Bonds	0.050

The Board of Directors has mandated that from the 600,000 investment, at least 55 percent of the investment consists of a combination of municipal and federal bonds. At least 30 percent Blue Chip Stock. No more than 15 percent High Tech Stock.

Formulate this portfolio selection problem using linear programming. (DO NOT SOLVE THE PROBLEM)

Let:

X1 = $ invested in Municipal Bonds

X2 = $ invested in High Tech Stocks

X3 = $ invested in Blue Chip Stocks

X4 = $ invested in Federal Bonds

Questions:

What is the Objective function formula?

What is the Constraint for at least 55% to municipal bonds and federal bonds?

What is the constraint for no more than 15 percent High Tech Stock investment?