Question

Please help me if you can.

Answer 1

Answer:

30. $3.85

31. $2.22

Explanation:

30. The time duration of the kitchen clock is left on = All day = 24 hours

The power rating of the kitchen clock, P = 4 watts

The electricity cost in Alberta, R = $0.11 per kilowatt hour

The total number of hours the kitchen clock is on during the year, 't', is given as follows;

t = Number of hours per day × Number of days per year

∴ t = 24 hours/day × 365 days/year = 8,760 hours

The energy consumption of the kitchen clock, per year, E = P × t

∴ E = 4 watts × 8,760 hours = 35,040 watts-hour = 35.040 kw·h

The cost of operating the clock in one year, C = E × R

∴ Operating cost for the kitchen clock

∴ C = 35.040 kw·h × $0.11/(kw·h) = $3.8544 ≈ $3.85

The cost of operating the clock in one year, C ≈ $3.85

31. The power rating of the ghetto blaster, P = 28 watts

The time duration the ghetto blaster was on during an average month = All day = 24 hours

The number of days during an average month, n = 30 days

The cost of electricity in Alberta, R = $0.11 per kilowatt hour

The time in hours the ghetto blaster was on, t = 30 days/month × 24 hours/day

∴ t = 720 hours per month

The cost of operating the ghetto blaster in one month, C = P × t × R

∴ C = 28 W × 720 hours × 1 kw·h/(1000 w·h)× $0.11/(kw·h) = $2.2176

∴ The cost of operating the ghetto blaster in one month, C ≈ $2.22