Each day that a library book is kept past its due date, a $0.30 fee is charged at midnight. Which ordered pair is a viable solution if x represents the number of days that a library book is late and y represents the total fee?

The total fee is $0.30 multiplied by the number of late days, so y = 0.30x. For 8 days late, the fee is 0.30 × 8 = $2.40, making (8, 2.40) viable. The other choices either use negative or fractional days, or give a fee that does not match the number of days.

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