Let t represent the time
Let C(t) represent the charge at a particular time
For the first 2 hours, the charge is $4 per hour
This can be expressed mathematically as:
C(t) = 4t for 0 < t ≤ 2
For the next 4 hours, the charge is $2 per hour
This can be expressed mathematically as:
C(t) = 8 + 2(t-2) for 2 < t ≤ 6
C(t) = 2t + 4 for 2 < t ≤ 6
For the last 2 hours, there is no charge
C(t) = 16 for 6 < t ≤ 8
This can be written summarily as: