Robert takes twice as much time as Tom and thrice as much time as George to complete a work. If working together, they can complete it in 23 hours, then find the time that Tom will take to complete the work.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 69 hours.
Given that
Robert takes twice as much time as Tom and thrice as much time as George
The time ratio of Robert, Tom, and George = 6 : 3 : 2
The efficiency of Robert, Tom, and George = (1/6) : (1/3) : (1/2) = 1 : 2 : 3
If they work together, they can complete it in 23 hours
Hence, Tom will take time to complete the work = 6 × 23/2 = 69 hours