Compact fluorescent lamps (CFLs) have become required in recent years, but do they make financial sense? Suppose a typical 60-watt incandescent light bulb costs $.39 and lasts 1,000 hours. A 15-watt CFL, which provides the same light, costs $3.10 and lasts for 12,000 hours. A kilowatt-hour of electricity costs $.115, which is about the national average. A kilowatt-hour is 1,000 watts for 1 hour. If you require a return of 11 percent and use a light fixture 500 hours per year, what is the equivalent annual cost of each light bulb? (Negative amounts should be indicated by a minus sign. Do not round intermediate calculations and round your answers to 2 decimal places, e.g., 32.16.)
Equivalent annual cost 60-watt incandescent light bulb $_______?
Equivalent annual cost Compact fluorescent lamps $_______?