how many hours can a full body tattoo take?

i am running a competition in a care home and we have vouchers for a tattoo shop and thought we need to do this as a separate competition at the fete to ensure tattoo likers win the prize, so we thought we would have a guess how long this tattoo take competition, I have found pictures on the internet of full body tattoos but they just seem to have costs, not hours, I need to be able to print a full picture with a how many hours this took next to it

if any tattoo artists here have a photo of a tattoo they have had done and know the hours and will let me print it out to raise money for the care home that would be great

I have asked the tattoo shop in question and they are quite a new shop so didn't have nay images themselves that I can use for the hours

thank you for your help in this matter

vici