Hicould anyone help me to solve this question

A tractor manufacturer makes two lines of bull dozer, model E-9 and model F-9. Business is booming and they know they will be able to sell as many dozers as they can make for the coming month. Every dozer requires a certain amount of production time in the two departments, A and B; the company has available a total of 150 hours in Department A, and 160 hours in Department B. Each E-9 requires 10 hours in Department A and 20 hours in Department B. Each F-9 requires 15 hours in Department a, and 10 hours in Department B. There is however only one testing department and company policy dictates that a minimum of 135 hours of bulldozer testing is required every month. It takes 30 hours to test an E-9 dozer but only 10 hours to test an F-9 dozer. Furthermore, because the F-9 dozer is tied to a government grant, the company must make at least one F-9 dozer for every three E-9 dozers produced. The firm is also committed by union agreements to produce at least 5 of these dozers every month. Each E-9 yields a profit of $5,000 and each F-9 generates $4,000 of profit. Determine the best product mix of bull dozers to maximize total profit of the firm. 1) Formulate a linear model. Give clear definitions to your decision variables. 2) Solve the problem graphically - show all the constraints and the objective function and indicate the optimal solution on your graph. DO NOT submit a solver solution