Answer:
C. 13.78 ≤ x ≤ 18.98
Step-by-step explanation:
The rate for Company B is show as 17.4 cents per kWh. That for Company D is shown as 14.8 cents per kWh. The savings obtained by using Company D is ...
17.4 - 14.8 = 2.6 . . . . cents per kWh
Then to find the savings a household would experience, we multiply this savings rate by the monthly usage rate of the household.
530 kWh × $0.026/kWh = $13.78
730 kWh × $0.026/kWh = $18.98
So for household usage between these energy values, the savings (x) using Company D will satisfy ...
13.78 ≤ x ≤ 18.98