A takes 4 times as much time as B or 5 times as much time as C to finish a piece of work. Working together, they can finish the work in 4 days. B can do the work alone in:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 10 days
Given:
A takes 4 times as much time as B or 5 times as much time as C to finish a piece of work.
Working together, they can finish the work in 4 days.
Concept used:
1. Efficiency (work done per day) of workers is inversely proportional to the time taken by workers to complete a particular task.
2. Total work = Efficiency (Work done per day) × Total time taken
Calculation:
Let the efficiency of A be P.
Hence, the efficiencies of B and C are 4P and 5P respectively.
Total work = 4 × (P + 4P + 5P) = 40P units
Now, B can do the work alone in = 40P/4P = 10 days
B alone can do the work in 10 days.