John can complete a piece of work in 6 days working 8 hours each day and Manu can complete it in 3 days working 4 hours each day. How long will they take to complete it, working together 9(3/5) hours a day?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 1 day.
Given:
John can complete a piece of work in 6 days working 8 hours each day
Manu can complete it in 3 days working 4 hours each day
Calculations:
Total amount of hours John worked = 48 hours
Total amount of hours Manu worked = 12 hours
Total work (LCM of 48 and 12) = 48 units
Efficiency of John = 48/48 = 1 unit
Efficiency of Manu = 48/12 = 4 units
Time required to complete the whole work in 9(3/5) hours per day = (48/(1 + 4) × 9(3/5))
= (48 × 5)/(5 × 48) = 1 day