Although typically, electricity customers are charged based merely on the total number of kilowatt-hours they consume, some utilities have payment plans designed to encourage customers to shift their energy use to off-peak times. Suppose that a utility charges most customers a flat 7.9 cents/kWh under their standard plan, but under a special time-of-use plan, it charges 3 cents/kWh for off-peak times (between 10 p. m. and 11 a. m. on weekdays) and 16 cents/kWh at other times. If a customer always consumes electricity at the same rate, which plan should he or she sign up for? (Text Problem Number 12)