Question : A small business can install its own interoffice telephonesystem for : 148576

A small business can install its own interoffice telephonesystem for a fixed cost of $4,000 and a variable cost of $59.9 pertelephone. The system will have a life of l0 years, no salvagevalue, and maintenance costs of $6 per phone per year. Thetelephone company will install a comparable system for a monthlycharge of $l6.5 plus $3.39 for each phone. If the interest rate is12% how many phones will be required to justify the privately ownedsystem?