Andrewandrew can paint the neighbor's house 4 times as fast as bailey. the year andrewandrew and baileybailey worked together, it took them 9 days. how long would it take each to paint the house?

Andrew can do 4 times faster
So 1 Andrew is equal to 4 Bailey
1 Andrew and 1 Bailey =  5 Bailey

5 Bailey takes 9 days
1 Bailey take 9 x 5 days = 45 days

Bailey takes 45 days
Andrew can do it 4 times faster
so Andrew needs 45/4 days 
Andrew needs 11.25 days

Andrew will take 11.25 days to paint the house.
Bailey will take 45 days to paint the house.

Wouldn’t it be six if all intervals are the same?