Final answer:
The rate of change for this situation is $4 per hour.
Step-by-step explanation:
The rate of change in this situation is $4 per hour. This means that for every hour the babysitter works, the cost increases by $4. The flat fee of $10 does not change based on the number of hours worked, so it does not contribute to the rate of change.
To calculate the rate of change, we can use the formula:
Rate of change = change in cost / change in hours
Since the flat fee does not change, the change in cost will always be $4 for each additional hour worked.
So, the rate of change is $4 per hour.