• B.15 Walter Wallace is trying to determine how many units each of two commercial multiline telephones to produce each day.

One of these is the standard model; the other one is the deluxe model. The profit per unit on the standard model is $40, on the deluxe model $60. Each unit requires 30 minutes assembly time.

The standard model requires 10 minutes of inspection time, the deluxe model 15 minutes. The company must fill an order for six standard phones. There are 450 minutes of assembly time and 180 minutes of inspection time available each day. How many units of each product should be manufactured to maximize profits?