Answer:
a) cost per book: $6
b) delivery fee: $3.25
Step-by-step explanation:
a)
If we assume the cost per book and the delivery fee are constant, then we can find the cost of 2 books by subtracting the cost for 4 books from the cost for 6 books
cost per book = (cost for 6 books - cost for 4 books)/(6 -4)
= ($39.25 -27.25)/2 = $12/2 = $6 . . . . . cost per book
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b)
The delivery charge will be the difference between the delivered cost and the cost of the books. For 4 books, that is ...
delivery charge = $27.25 -4(6.00) = $3.25
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Additional comment
The relationship between delivered cost and number of books is not proportional. There are no proportions to solve in this problem.
