Final answer:
The painter's unit rate of change of dollars to time is $60 per hour.
Step-by-step explanation:
To find the painter's unit rate of change of dollars for time, we need to determine the amount paid per hour. We can do this by dividing the amount paid by the total hours worked.
The painter worked a total of 5 + 4 + 6 = 15 hours in three days.
The total amount paid to the painter is $300 + $240 + $360 = $900.
Therefore, the painter's unit rate of change of dollars concerning time is $900 / 15 = $60 per hour.