You can upgrade lighting at your factory to LED bulbs that cost $6.95 each and last an average of 5 years. It costs $3 in labor to change a bulb. Over a 10-year period, about how much will it cost per year to install LED bulbs in 100 lamps and change the bulbs when they burn out?

Question

Kaleb Schwartz

Mathematics

3 August, 19:48

You can upgrade lighting at your factory to LED bulbs that cost $6.95 each and last an average of 5 years. It costs $3 in labor to change a bulb. Over a 10-year period, about how much will it cost per year to install LED bulbs in 100 lamps and change the bulbs when they burn out?

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Alisa · Answer 1

Each bulb and the labor to install it costs

... $6.95 + $3 = $9.95

100 bulbs and 10 years totals (100*10) = 1000 bulb·years. For the price of $9.95, you purchase 5 bulb·years, so the total cost for 1000 bulb·years is

... (1000 b·y) * ($9.95 / (5 b·y)) = $1990

Over a 10-year period, installation and replacement of 200 bulbs in 100 lamps will cost $1990. Then the per-year cost is ...

... $1990 / (10 yr) = $199/yr