The two systems are considered for a project. Suppose MARR is at 10% per year, determine how many units must be used to rationalize the system B. Use the electricity rate costs of Php 0.08/kwH for the calculation. Installation Cost Efficiency Useful Life User Costs per unit Annual Maintenance Cost Power Output System A Php 32,000 78% 10 years Php 0.24 Php 75 28kW System B Php 45,000 90% 15 years Php 0.22 Php 100. 34kW