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
N0.13
C
N3.90
D
N39.00
E
N234.00
Verified Correct Answer: B.
Physical Principles & Numerical Solution
PT = (5 x 50) + (100 x 4)
= 650watts
Energy(kWhr) = 650 x 10-3 x 10
= 6.5 kWhr
1kWhr cost 2 kobo ; 6.5 kWhr will cost \(\frac{2 \times 6.5}{1}\)
= 13 kobo
Source: Myschool Past Questions Archive (Record #28739)