SSC MTS 6 Aug 2019 Shift 3 Paper

Let the number of days taken by Rohit be x.
Since efficiency is inversely proportional to the time taken.
⇒ Number of days taken by Mohit = x/5
According to the question,
⇒ x – x/5 = 28
⇒ 4x/5 = 28
⇒ x = 35 days
Alternate Solution:
Let the efficiency of Rohit be 1.
⇒ Mohit’s efficiency = 5
Let Rohit can complete the work in x days.
⇒ Mohit’s efficiency × time = Rohit’s efficiency × time
⇒ 5 × (x – 28) = 1 × x
⇒ 4x = 5 × 28
⇒ x = 35
⇒ Total work = Rohit’s efficiency × time = 1 × x = 35
⇒ Rohit alone complete the work = Total work/ Rohit’s efficiency = 35 days
∴ Rohit alone complete the work in 35 days.