Correct Answer - Option 3 : 8 days
Given:
The ratio of work efficiency of A and B is 6 ∶ 5 and that of B and C is 4 ∶ 3.
A can do a piece of work in 5 days.
Concept used:
Work = Time × Efficiency
Time = Work/Efficiency
Calculation:
A ∶ B = (6 ∶ 5) × 4 = 24 ∶ 20
B ∶ C = (4 ∶ 3) × 5 = 20 ∶ 15
A ∶ B ∶ C = 24 ∶ 20 ∶ 15
Time taken by A = 5 days
Work = Time × Efficiency
Work done by A = 5 × 24 = 120 work
Time taken by C = Total work/Efficiency
⇒ Time taken by C = 120/15 days
⇒ 8 days
∴ C can alone do a piece of work in 8 days.
