please answer all of question 7

7. Consider a proposal to enhance the vision system used by a postal service to sort mail. The new system is estimated to cost $1.2 million and will incur an additional $250,000 per year in maintenance costs. The system will produce annual savings of $600,000 each year (primarily by decreasing the percentage of misdirected mail and reducing the amount of mail that must be sorted manually). The MARR is 12% per year, and the study period is five years at which time the system will be technologically obsolete (worthless). 7-1. (1 point) What is the PW of this proposal? 7-2. (2 points) Determine how sensitive the decision to invest in the system is to the estimates of investment cost. 7-3. (2 points) Determine how sensitive the decision to invest in the system is to the estimates of annual savings