Question 9 (10 points) Maintenance costs for a regenerative thermal oxidizer have been increasing uniformly for 5 years. If the cost in year 1 was $8,000 and it increased by $900 per year through year 5, the present worth of the costs at an interest rate of 5% per year is closest to: O $31,673 O $36,502 O $42,049 O$44,141