Question

B is twice as efficient as A is and C is thrice as efficient as A. If B and C together completes a piece of work in 17 days then in how many days A alone will complete the same work?
1. 80 days
2. 85 days
3. 78 days
4. 82 days

Answer 1

Correct Answer - Option 2 : 85 days

GIVEN:

B's efficiency = 2 × A's efficiency

C's efficiency = 3 × A's efficiency

time taken by (B + C) = 17 days 

FORMULA USED:

work = efficiency × time

CALCULATION:

let A's efficiency = x

∴ B's efficiency = 2x 

C's efficiency = 3x

work done by (B + C) = 17 × 5x = 85x

∴ time taken by A alone = 85x /x = 85 days