Low-energy lightbulbs typically cost $3.50, have a life of nine years, and use about $1.60 of electricity a year. Conventional lightbulbs are cheaper to buy, for they cost only $.50. On the other hand, a e real discount rate is 5%, what is he equivalent annual costo places.) e two roducts? o not round inte mediate ca a ations n er our answers as apo tive alue rounded to 2 decimal Equivalent Annual Cost Low-energy lightbulbs Conventional lightbulbs b. Which product is cheaper to use? Low-energy lightbulbs O Conventional lightbulbs