A better estimate would be something that is closer to one you had before...
I think it would be 11 because if it was 12 hours it would been way more then $1265. they are asking you for hours not minutes. I am pretty sure it would be 11. I hope this helped!
4.166 cans !
6*75 = 450 sq.ft
so approximately 4.166 cans will be required !
