Assignment

An illuminating engineer has the following cost comparison for three kinds of bulbs $($each giving the same amount of illumination$).$

$\backslash$table$[[,$LED,CFL$,$Incandescent$],[$Light bulb projected lifespan,$\backslash$table$[[25,000],[$hours$]],\backslash$table$[[10,000],[$hours$]],\backslash$table$[[1,200],[$hours$]]],[$Watts per bulb $($equiv$.60$ watts$),8\mathrm{.}5,14,60],[$Cost per bulb,$$5,$$$2,$$$1$