Using a proportional relationship, the ordered pair that is a solution if x represents the number of days that a library book is late and y represents the total fee is:
(3, 0.9).
<h3>What is a proportional relationship?</h3>
A proportional relationship is a function in which the output variable is given by the input variable multiplied by a constant of proportionality, that is:
y = kx
In which k is the constant of proportionality.
For this problem, each day, the free is increased by $0.3, hence the constant is k = 0.3 and the function is:
y = 0.3x.
Then after three days, the total fee is:
y = 0.3 x 3 = 0.9.
And the ordered pair is:
(3, 0.9).
More can be learned about proportional relationships at brainly.com/question/28291848
#SPJ1