Question

2 bulb of 40 wAat a lighted for 8 hour daily find the cost of electric energy consumed by than one week at rupees 3 per unit

Answer 1

Hey.

Here is the answer.

Power of each bulb = 40 W

runnjng time = 8 hr daily

and for 1 week or 7days

so total time = 7× 8 hr = 56 hr

Power of 2 bulbs = 2×40 W

= 80 W

= 0.080 kW

As 1 kWh = 1 kW × 1 hr

so, total energy consumed = 0.08×56 kWh

= 4.48 kWh

or 4.48 units.

As rate is rs. 3 per unit

so, total weekly cost = 4.48×3 = rs. 13.44

Thanks.

Answer 2

Hey friend
here is your answer

power = 40 W

time = 8 × 7

rate of cost = rs.3

and,

quantity of bulb = 2

as,
$cost \: of \: electricity = \frac{ \: \: power \times time \times rate \: f \: cost \: }{1000} \times 2 \\ cost \: of \: electricity = \frac{40 \times 8 \times 7 \times 3}{1000} \times 2 \\ cost \: of \: electricity = rs.13.44$

glad to help you
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thank you.