Answer:
y = 0.07n + 0.2
Explanation:
y = mx + b
m: slope → amount cost is increasing
b: y-intercept → the cost at 0 minutes
cost is increasing by (m): 0.07 cost increase by minute
Time at 5 minutes + the amount cost increase = Time at 5 minutes
0.55 + m = 0.62
-0.55 -0.55 m = 0.07
Time at 6 minutes + the amount cost increase = Time at 5 minutes
0.62 + m = 0.69
-0.62 -0.62 m = 0.07
....and so on
the cost at 0 minutes (b): 0.2 is the cost at 0 minute (start)
cost at n minutes
= cost is increasing by (m) x n of minutes + cost at 0 minutes (b)
cost at 5 minutes
= cost is increasing by (m) x 5 minutes + cost at 0 minutes (b)
0.55 = 0.07 x (5) + b
0.55 = 0.35 + b
- 035 - 035
b = 0.2