Final answer:
The rate of change of money in Fabian's savings account per week is $10.
Step-by-step explanation:
The rate of change of money in Fabian's savings account per week can be found by calculating the difference in savings over the given time period and dividing it by the number of weeks.
To find the rate of change, subtract the initial amount from the final amount and divide the result by the number of weeks:
Rate of change = (Final amount - Initial amount) / Number of weeks
Using the given information, the rate of change of money in Fabian's savings account per week is:
Rate of change = ($400 - $350) / (9 weeks - 4 weeks) = $50 / 5 weeks = $10 per week.