Rohan takes 10 hours to mow a large lawn. He and Mohan together can mow it in 4 hours. How long will Mohan take to mow the lawn if he works alone?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. hours.
We know,
Work done = Efficiency × Time taken
Now,
Total work done (LCM of 10 and 4) = 20 units
Efficiency of Rohan = 20/10 = 2
Efficiency of Rohan and Mohan = 20/4 = 5
Hence, efficiency of Mohan = 5 - 2 = 3
Time required by Mohan = 20/3 hours