What is the cost of running five 50W lamps and four 100W lamps for 10 hours if electrical energy costs 2 Kobo per KWh?
A
N0.65
B
N0.39
C
N3.90
D
N0.13
Verified Correct Answer: D.
Physical Principles & Numerical Solution
POWER = energy consumed/time
Energy consumed = power x time
energy consumed = \(\frac{(5 \times 50) + (4 \times 100) \times10}{1000}\)
= 6.5KWh.
but 1KWh = 2kobo
then 6.5KWh = 6.5 x 2 = 13kobo →#0.13
Source: Myschool Past Questions Archive (Record #56903)