Answer: 17 months
Step-by-step explanation:
Lease amount = $1000 per month
Purchase amount = $15000
Interest rate = 0.5% per month
Let the number of months that us required for the system to breakeven be m. Therefore,
m × 1000 = 15000 + ( m × 80) + (m × 15000 × 0.5)/100
1000m = 15000 + 155m
1000m - 155m = 15000
845m = 15000
m = 15000 / 845
m = 17 months