A can do a piece of work alone in 30 days. B is 25% less efficient than A, while C is $33\frac{1}{3}$% more efficient than B. In how many days can A, B and C, working together, complete the work?
Answer & explanation
Correct answer: option 2
A = 30 days,
B is 25% less efficient than A, while C is 33.33% more efficient than B, therefore,
A : B : C = 4 : 3 : 4 (Efficiency)
⇒ Total work = 4 x 30 = 120 units, ..(Efficiency × Days = Total work)
⇒ Time required for A + B + C to complete the work = \(\frac{120}{4+3+4}\) = \(\frac{120}{11}\) days ..(\(\frac{Work}{Efficiency}\) = Time)