Problem $10-29$ Break$-$Even Cost $[$LO$2]$

Light emitting diode $($LEDs$)$ light bulbs have become required in recent years, but do

they make financial sense? Suppose a typical $60-$watt incandescent light bulb costs $$\mathrm{.}41$

and lasts for $1,000$ hours. A $15-$watt LED, which provides the same light, costs $$3\mathrm{.}20$ and

lasts for $12,000$ hours. A kilowatt hour of electricity costs $$\mathrm{.}117.$ A kilowatt$-$hour is $1,000$

watts for $1$ hour. However, electricity costs actually vary quite a bit depending on location

and user type. An industrial user in West Virginia might pay $$\mathrm{.}04$ per kilowatt$-$hour

whereas a residential user in Hawai might pay $$\mathrm{.}25.$ You require a return of $9$

percent and use a light fixture $500$ hours per year. What is the break$-$even cost per

kilowatt$-$hour? $($Do not round intermediate calculations and round your answer to $6$

decimal places, e$.$g$.,32\mathrm{.}161616.)$