A man can do a job in 10 days. His father takes 15 days and his son finishes it in 20 days. How long will they take to complete the job if they all work together?
1
60/13 days
2
13/60 days
3
19/25 days
4
25/19 days
5
28 days
A man can do a job in 10 days. His father takes 15 days and his son finishes it in 20 days. How long will they take to complete the job if they all work together?