Answer:
B
Step-by-step explanation:
Since the person used >200 kWh that month, you would use the bottom equation: 0.15(x-200)+20.
(BTW, the x>200 or x≤200 means if they used more or less than/equal to 200 hours)
From there, you can plug in the number of hours for x, which is 400. So, 0.15([400]-200)+20
0.15(200)+20
30+20
50
