Correct Answer - Option 1 : 3
Given:
A is twice as efficient as B
B is thrice as efficient as C
C alone can do work in 30 days
Concept Used:
Total work = Time taken × Efficiency
Calculation:
A = 2B
B = 3C
A ∶ B = 2 ∶ 1
B ∶ C = 3 ∶ 1
A ∶ B ∶ C = 6 ∶ 3 ∶ 1
C alone can do work in 30 days
So, total work = 1 × 30 = 30 units
Efficiency of (A + B + C) = 6 + 3 + 1 ⇒ 10 units
∴ Work completed by A, B and C = 30/10 = 3 days