Work problem

Here is the answer:
Daisy did 2/5ths or %40 of the barn in those two days as she can do the whole lot in 5 days she did 2/5ths or %40 in 2 days so thats %40 of the barn done.
Didith did 2/8ths or %25 of the barn in those two days, 
so the amount of barn painted in the first two days is: 1/4 + 2/5 which equals %65 of the barn complete in the first two days. so there is %35 of the barn left to paint and only Daisy (who can paint %20 of the barn in one day) 
so to figure out how many days it takes Daisy to paint %35 of the barn this is what to do:
%20 = 1day %35 - %20 = %15 5x5x5x5 = 20 5x5x5 = 15 therefore it takes Daisy 1/4 of a day to paint %5 of the barn therefore it takes Daisy 3/4 of a day to paint %15 of the barn (i hope you are following me here!) 1 + 3/4 = one and three quarters of a day
Therefore it took Daisy one and three quarter days to paint the remaining %35 of the barn.
So it took Days one and three quarter days to finish the job after Didith left.
Hope this is helpful
Emmanuel