If p is a prime, which one of the following could be a prime also?
1 answer:
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Answer:
$148.4
Step-by-step explanation:
Given:
Power consumed by the energy-efficient lightbulb = 27.0 W = 27.0 × 10⁻³ kW
Power consumed by the conventional lightbulb = 100 W = 100 × 10⁻³ kW
Lifetime of the energy-efficient lightbulb = 10,000 h
Lifetime of the conventional lightbulb = 750 h
Cost of the energy-efficient lightbulb = $4.60 per bulb
Cost of the conventional lightbulb = $0.50 per bulb
Energy cost = $0.20 per kilowatt-hour
Now,
The total cost of energy-efficient lightbulb for 10,000 hours
= cost of bulb + energy cost
= $4.60 + ( 27.0 × 10⁻³ kW × $0.20 kW/h × 10,000 h)
= $4.60 + $54
= $58.60
Now,
For the life of 10,000 hours number of conventional bulbs required
=
=
= 13.33 ≈ 14 bulbs
Thus,
The total cost of conventional bulb for 10,000 hours
= cost of bulb + energy cost
= ( $0.50 × 14 ) + ( 100 × 10⁻³ kW × $0.20 kW/h × 10,000 h)
= $7 + $200
= $207
Therefore,
The total savings = $207 - $58.60 = $148.4