The answer is (8, 2.40).
We can deduce this because if x is negative, it means the book is not late; it's early! We can cross out the first two answers. We know the third one is wrong because the fee is charged on midnight, so the fee for 4.5 days late would be the fee for 4 days late, which would be 1.20, not 1.35. for 8 days, the cost would be (8*0.30) = 2.40, which is what we have for y in the pair. Therefore, (8, 2.40) is the answer.
Hope this helps! :)
