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:
Answer & explanation
Correct answer: option 1
efficiency ∝ \(\frac{1}{time}\)
A : B : C
time 4 : 1
5 : 1
______________
20 : 5 : 4
efficiency 1 : 4 : 5 ⇒ 10
work = efficiency x time taken = 10 x 4 = 40
time taken by B to complete the same work = \(\frac{40}{4}\) = 10 days