1. Sewing rate is irrelevant because even if she used ONLY blue squares, she could sew 124 squares in 31 days. That stuff is thrown in just to confuse you. The cost function is simply number of blue squares times 80 cents plus number of white squares times $1.20, i.e., C = 0.8b + 1.2w, which is answer b.
2. The greatest number the customer will buy, is 12. If there must be at least one of each kind in the dozen, then the Baker's greatest profit will come when there is only one glazed doughnut, i.e, the baker's profit will be 11 x 40￠ + 1 x 15￠ = $4.55, answer a.
1) b ? ? ? cost is 0.80 for each blue and 1.20 for each white
2) 1 glazed + 11 jelly = 0.15 + 11(0.40) = 0.15 + 4.40 = 4.55, answer a.
Not too sure about the first one.
2nd one answer is (a.)
Because the maximum profit he can make is 4.80 (by getting all jelly doughnuts at 0.40 X 12). But since the customer wants to try at-lest one of both types, we can say he had 11 jelly doughnuts and 1 glazed doughnut. So the new calculation would be, (0.4 X 11) + (0.15 X 1) = 4.55