Answer:
1) c = 25m + 90
2) c = 17m; $85
3) c = 10m + 15; $135
Step-by-step explanation:
Let m = number of months
1)
c = 25m + 90
2)
c = 17m
For 5 months, m = 5.
c = 17m = 17 × 5 = 85
$85
3)
c = 10m + 15
1 year = 12 months, so m = 12
c = 10m + 15 = 10 × 12 + 15 = 120 + 15 = 135
$135