Santiago Co. provides excellent service and high-quality injection molding solutions in Chile. It relies on molding process technologies to meet the precision and performance requirements since qualified custom molder includes one injection-molding machine with their two fitting dies. Due to differences in cycle times, cavity (part) configuration, the die A can produce 100 units of 120litre wheelie bins in 5 hours, while the die B can produce the same quantity of 160-liter wheelie bins in 4 hours. Santiago’s machinery system has a maximum capacity of 32 working hours per week. And although they operate on an ordering scheme, they want to utilize most of their fixed investment each week. After producing, wheelie bins are stored in a 12,400 cubic feet stockroom, in which 100 units of 120 litre wheelie bin requires 1,400 cubic feet of space and 100 units of 160litre wheelie requires 1,800 cubic feet. The contribution of the 120 and 160 litre wheelie bins is $5 and $4 per unit. Due to the huge amount of residential garbage and the historical record, the weekly demand for a 160-liter wheelie bin is not less than 240 units, and the demand for 120-liter wheelie bins would not exceed the demand of larger ones more than 45 units.

1. How many units of each type should be produced each week to maximize the total contribution?

2. There is a fluctuation in the demand for 160-liter wheelie bins. Determine the range in which the price of 160-liter wheelie bins may change to keep the optimal solution unchanged?