Calculating energy costs.?

Long question, I'll try to make it short.

Costco sells these LED flood light bulbs that use 5 watts of electricity, but give off the equivalent of a 60 watt bulb. The LED bulb costs $15.00 (total including tax) while a old fashioned incandescent flood light bulb costs $5.00 (also total price including tax)

The LED flood light bulb claims to last 10 times the life of the incandescent bulb. And electricity rates are about 13 cents a kilowatt hour where I live.

How long will it take for the LED light bulb to pay for itseff if used 12 hour a night Say from 7.00 PM to 7.00 AM

electric costs 13 cents KWH, LED energy usage 5W VS. Incandescent 60W

Thanks. I really suck at math. Is it worth it to get many of those expensive LED bulbs to put up all over?
Sorry, I forgot to mention, I want to make it an even comparison, I want to compare an old fashioned 60W flood light bulb and a LED flood light bulb that uses 5W but gives off 60W worth of light.
 
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