A. 190 sec
Feedback That means Rohan takes 10 sec to cover 50 meters
=> Rohan will cover 1000 meters in 200 sec
Mohan is giving a start of 10 sec. means Mohan will take 10 sec less than Rohan to cover 1000 m.
so, Time taken by Mohan to cover 1000 m is 190 sec.