Question 318978
A & B can do a job in 40/3 days
so they do 3/40 of the job in 1 day.
..
A does in 20 days.
he does 1/20 of the job in 1 day
..
3/40-1/20 = 3-2 /40
=1/40 of the jobin 1 day
So B does the job in 40 days.