The maintenance and operations costs for a piece of equipment are estimated to be $900 the first month and increase by $20 per month over the equipment's 3-year life. For budgeting purposes, the owner wants to set aside a uniform amount each month. If the owner can invest at 9% per year, compounded monthly, what amount should he invest each month?
a. $35.60
b. $37.80
c. $40.00
d. $42.25