Question

The electric bill for a family for a month is $120.

a. Assuming 30 days in the month, what is the cost per day?

b. Based on 15-h days, what is the cost per hour?

c. How many kilowatthours are used per hour if the cost is 12¢/kWh?

d. How many 60 W lightbulbs (approximate number) could you have on to use up that much energy per hour?

e. Do you believe the cost of electricity is excessive?

Answer 1

a. The cost per day is $120/30=$4.

b. The cost per hour is $4/15=27¢/h

c. The energy used is

$$E=27/12=2.22\text{ kW}·\text h.$$

d. The number is

$$N=2222/60=37.$$

e. I believe it is decent for some countries.