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A landlord has eight 40W electric light bulbs, four 60W bulbs and two 100W bulb ...


Question

A landlord has eight 40W electric light bulbs, four 60W bulbs and two 100W bulb in his house. If he has all the points on for five hours daily and if N.E.P.A. charges 5k per unit, his bill for 30 days is

Options

A) N5.70

B) N7.23

C) N3.65

D) N8.05

E) N4.50


The correct answer is A.

Explanation:

Total power = (8 x 40) + (40 x 60) + (2 x 100)

= 760W

Energy(Kwhr) = power x time

= 760 x 10-3 x 150

= 114kwhr.

If, 1kwhr. cost 5k

thus, 114 kwhr. will cost 5 x 114

= N5.70


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Dicussion (1)

  • Total power = (8 x 40) + (40 x 60) + (2 x 100)

    = 760W

    Energy(Kwhr) = power x time

    = 760 x 10-3 x 150

    = 114kwhr.

    If, 1kwhr. cost 5k

    thus, 114 kwhr. will cost 5 x 114

    = N5.70