Answer:
It is not a proportional relationship
Explanations:
Note that:
for a proportional relationship, there is always a constant of proportionality
A proportional relationship is of the form
y = kx
Let the cost be y
Let the number of hours be x
If k is the same for x = 4 hours, y = $10 and x = 5 hours, y = $12, then the relationship is proportional
For x = 4, y = 10:
y = kx
10 = 4k
k = 10/4
k = 2.5
For x = 5, y = 12
y = kx
12 = 5k
k = 12/5
k = 2.4
Since k is not constant (not the same) for both cases, the relationship is not proportional