Cell phone regions
Region A: Too many phones are produced to satisfy both the quantity and labor limits. All points in A are for more than 25 phones and more than 80 hours.
Region B: In this region all combinations of no-frills and hi-end phones are within the 80-hour labor limit, but exceed the 25-phone maximum.
Region C: All combinations of no-frill and hi-end phones are within the 80-hour, 25 phone limits.
Region D: In this region all combinations of no-frills and hi-end phones are within the 25-phone manufacturing capacity, but exceed the 80-hour labor limit.