(An investment problem) A client has approached a stockbroker with the following request: invest $100,000 for maximum annual income under the three conditions: Spread the investment over no more than three different stocks Put no more than 40 percent of the money into any one stock Put a minimum of $10,000 into oil stock, The broker has identified three stocks for the investing the funds. Their estimated annual returns and price per share are shown in the following table: Stock Price/share Estimate Annual return/share Oil $120 $11 Auto $52 $4 Pharmaceutical $18 $2 Formulate & solve a linear programming model to determine the investment so as to maximize the total estimated returns.