Let's say Bailey takes "b" days to paint it.
and Andrew takes "a" days to paint the same house.
now, Andrew is 6 times faster than Bailey, therefore, if Andrew takes "a" days to do it, Bailey takes then "6a" days, or b = 6a.
now, the year they worked together, they finished it in 7 days.
so, after 1 day then, they have only done 1/7 of the whole work.
and Andrew for one day, has done 1/a of the house, whilst Bailey has done 1/b of the house or 1/(6a).