A can do a piece of work alone in 12 days. B is 20% more efficient than A, and C is 25% more efficient than B. In how many days can B and C together complete the work?
Answer & explanation
Correct answer: option 2
A = 12 days,
A : B : C
5 : 6
. 4 : : 5
⇒ 10 : 12 : 15 (Efficiency)
⇒ Total work = A x 12 days = 10 x 12 = 120 units ..(Efficiency × Days = Total work)
⇒ Time required by B + C to complete the total work = \(\frac{120}{27}\) = \(\frac{40}{9}\) days. ..(\(\frac{Work}{Efficiency}\) = Time)