It takes A and B, 3 and 6 hours, respectively, to complete a certain work. If they work on the alternate hour. How long will it take them to accomplish the task?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 4 hours
Given:
A and B take 3 and 6 hours to do a work
Concept used:
Work = Efficiency × time
Calculations:
Total work (LCM of 3 and 6) = 6 units
Efficiency of A = 6/3 = 2
Efficiency of B = 6/6 = 1
They work on alternate days,
⇒ 2 hours = 3 units
⇒ 4 hours = 6 units
Hence, the required time taken = 4 hours