Correct Answer - Option 3 : 45/2 days
Given:
Rohan is thrice as good as a workman as Rahul
Rohan finish a job = 60 days less than Rahul
Calculation:
The ratio of times taken by Rohan and Rahul = 1 : 3
∴ the time difference is (3 - 1) 2 days while Rahul takes 3 days and Rohan takes 1 day.
If the difference of time is 2 days, Rahul takes 3 days
If the difference of time is 60 days, Rahul takes (3/2 × 60)
⇒ 90 days
∴ Rohan takes 30 days to do the work.
Rohan’s 1 day’s work = 1/30
Rahul’s 1 day’s work = 1/90
∴ (Rohan + Rahul)’s 1 day’s work = 1/30 + 1/90
⇒ 4/90
⇒ 2/45
∴ Rahul and Rohan together can do the work in 45/2 days.