Five 80-W and three 100W are run for 8 hours. If the cost of energy is N5.00 per unit, calculate the cost of running the lamp. [1 unit = 1 kWh]

A. N280.00
B. N28.00
C. N7.20
D. N1.44

Correct Answer: Option B

B. N28.00

Explanation

P = (80 x 5 + 100 x 3)8

= 5600W

Cost = (5600/1000)×5 =N28