The “limited plan” offers a 15% discount for power usage between 7pm – 9am if most of your usage happens during that time. if not, then you lose your discount and you pay a 20% premium on the usage outside of that time. the cost per kilowatt hour is $0.05432. how much would you have paid in march if you used 450 kwh 7pm – 9am and 465 kwh 9am – 7pm?

The correct answer is:

$54.75.

Explanation:

We only receive the discount if the majority of our usage occurs between 7 pm to 9 am.  However, in the month of March we used 450 KWH between these hours and 465 KWH between 9 am to 7 pm; this means we lose our discount.

The rate per KWH is $0.05432; this means we pay

450(0.05432) = 24.444 for the hours of 7 pm to 9 am.

We also pay $0.05432/kwh for the hours of 9 am to 7 pm, but we have an additional 20% premium for the usage between these hours; this means we pay

465(0.05432)(1.2) = 30.31056, for a total of

24.444+30.31056 = 54.75456 ≈ 54.75

step-by-step explanation: