Answer:

Rate of change: 15 dollars per hour (or $15/hour)
Explanation:
Let E represent Franc's weekly earnings in dollars, and h represent the number of hours he works in a week. The function that describes Franc's weekly earnings (E) can be expressed as:

Here:
- 15h represents the amount he earns per hour.
- 30 is the fixed amount he receives weekly for car maintenance.
The rate of change, often referred to as the derivative in calculus, represents how much the dependent variable changes concerning the independent variable.
In this context, the rate of change of Franc's weekly earnings with respect to the number of hours worked is the coefficient of h, which is 15.
Therefore, the rate of change for this situation is 15 dollars per hour (or $15/hour).