Help with word problems!?

1)) Selena has 31 days to complete her quilt for the county fair. The blue squares in the quilt can be sewn at a rate of 4 squares per day, and the white squares at a rate of 7 squares per day. The quilt can have up to 96 squares total. The blue fabric b costs about $0.80 per square and the white fabric w costs about $1.20 per square. Selena wants to keep costs at a minimum. Write the function that describes the cost of the quilt.

Choose one answer.

a. 96 = 4b + 7w

b. f(b, w) = 0.80b + 1.20w

c. f(b, w) = 4b + 7w

d. 96 = 0.80b + 1.20w

2))A baker earns 15¢ profit per glazed doughnut g, and 40¢ profit per jelly doughnut j. If a customer wants to buy no more than a dozen doughnuts and wants to try at least one of each kind, what is the maximum profit the baker can earn?

Choose one answer.

a. $4.55

b. $3.30

c. $4.80

d. $1.80


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