An engineer has a fluctuating future budget for the maintenance of a particular machine. During each of the first 5 years, $10,000 per year will be geted. During the second 5 years, the annual budget will be $15,000 per year. In addition, $5000 will be budgeted for an overhaul of the machine at the | end of the fourth year, and again at the end of the eighth year. What uniform annual expenditure would be equivalent, if interest is 8% per year